The Defining Decade
Educational
Inspirational
Honest

The Defining Decade Why Your Twenties Matter--And How to Make the Most of Them Now

Meg Jay2012
New York Times bestselling psychologist Dr. Meg Jay uses real stories from real lives to provide smart, compassionate, and constructive advice about the crucial (and difficult) years we cannot afford to miss. Our "thirty-is-the-new-twenty" culture tells us the twentysomething years don't matter. Some say they are a second adolescence. Others call them an emerging adulthood. Dr. Meg Jay, a clinical psychologist, argues that twentysomethings have been caught in a swirl of hype and misinformation, much of which has trivialized what is actually the most defining decade of adulthood. Drawing from almost two decades of work with hundreds of clients and students, The Defining Decade weaves the latest science of the twentysomething years with the behind-closed-doors stories from twentysomethings, themselves. The result is a provocative read that provides the tools necessary to make the most of your twenties, and shows us how work, relationships, personality, social networks, identity, and even the brain can change more during this decade than at any other time in adulthood—if we use the time wisely. The Defining Decade is a smart, compassionate and constructive book about the years we cannot afford to miss.
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Reviews

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Amb@amberariel
4 stars
Mar 31, 2025

This book gave me a kick in my booty! A lot of the concepts are things we naturally know, but need to hear time and time again to get it ingrained. I appreciate that all of the advice is concrete, actionable items that can be implemented now, not later.

+4
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Emma@emmabutonline
5 stars
Jan 4, 2025

It’s been such a long time since I’ve walked away from a self-help book with questions that are actually making me a better person. I don’t want to oversell this book, but it was life changing. I’m definitely moving differently now.

+6
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Liyah 🤎@aallen1019
2 stars
Jun 17, 2024

I wanted so badly to like this book. I was grossly disappointed. Some may be due to poor marketing. Some due to real structural issues with the book for me. Let's start with marketing. The book's cover implies that its got essential and generalizable info that all 20-year-olds are missing and are going to want. Based on that I thought the book would be a lot more about mindset or frameworks or perspectives 20-year-olds don't have, and I was all in for that. I'm 22 and about to graduate college, so reading it even made me feel a little ahead of the curve, maybe like I was getting something proactively instead of reactively. This book wasn't that. In fact, I think if you're someone who would read this to be proactive, then this book isn't for you. This book starts from the assumption that all 20-year-olds are just stumbling around with a lack of self-awareness, half child half adult. This book is basically just a shake on the shoulders that says "hey, your twenties aren't a playground before your life starts. They're your life, and you need to use them wisely". Great, albeit obvious to me, but clearly not to this woman's clients point. If you're a planner who thinks about the future and how to get what you want, the one shining point of this book you've already got and can probably move on from. As for what the therapist suggests doing with your time? Hoping on the conveyer belt toward married suburban middle-class (white-coded) life. Now I'm sure some of this comes from the fact that things like good stable jobs, marriage, kids, and the whole nine yards happened to be of paramount concern to her clients and so because this book is, so client anecdote based it tips the scales. yet my issue is the author never acknowledges this as just one way of making a meaningful life in your twenties. Without the acknowledgment, the implication is that if you're not working towards what's basically the American dream, you're wasting your time. I do not vibe with that. I think the American dream is a pipe dream, and we need to be open to alternative ways of meaning-making and happiness in our lives. I really wanted to be open to this book's advice, but a lot of times I found myself put off by how much the book really just seemed to be saying "hey get with the program and start working on your American dream, join the rat race and you'll be better for it." I wouldn't recommend this to my friends UNLESS they were truly listless and unambitious not even considering that the life they're living now counts which honestly I could say that rather than give them this book and imply that they need to conform to capitalism to be happy.

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Monicap@insult_the_glory
4 stars
Apr 29, 2024

Decent. Interesting, with lots of cool things I didn't know that are actually really nice to know. Well-written. It kept my attention. Very enjoyable nonfiction book.

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Riley Bell@rikeyb
5 stars
Apr 16, 2024

Seriously, read this book. Very direct and eye-opening for considering the facts and putting our twenties into perspective rather than seeing them as a random and meaningless time to do whatever. But not in a hopeless, time has been wasted way. More like an encouraging, slap on the ass way. This book is for any “twentysomething” whether you are sure of most things or completely lost, or don’t even know what you are.

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Omar @sparsesuccess
3 stars
Apr 11, 2024

done! Useful advice, but definitely not the kind of deep dive I was after. Maybe if I slowed down reading it it would’ve rated higher. Even had a dedicated section on love, which barely read bc i have a phd in that

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JoAnna@lilipuddingdog
2 stars
Feb 21, 2024

To be honest, I think this book could have been an essay. A lot of chapters felt like fruitless reads, where you're going through her narrative example and left with no substantial "nugget" of truth in the end.

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Jack O‘Conner@miraluna
1 star
Jan 23, 2024

Was ein bullshit

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Zhomart M@zhomart
5 stars
Jul 3, 2023

I liked the book. Although, you have to be careful trusting many assumptions she makes, because all of them are based on her patients. If we think people who goes to therapy are ones who have 20something problems, then she might have a survivorship bias. But I really liked her tips and suggestions on how to live your 20es.

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Xin Ma@xym
2 stars
May 22, 2023

this could be a good book for an alien to earth learning about the individualism of 21st century career search coupled with the importance of strong and weak interpersonal relationships, but the concepts, though consolidated as fancy terms and theories, are quite basic

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Lara Ximenes@laraximenes
5 stars
May 21, 2023

The book every twentysomething should be reading. No one my age is thinking much about settling down and having kids at 20, but this is precisely the age we should be setting ourselves up for the future. The 30s might be too late to start pondering those things, after all.

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Isabella@isabellareads
3.25 stars
May 17, 2023

im currently going thru a weird transitional period of my life (graduating college, about to turn 21) so i decided to turn to this book for a lil bit of guidance and direction it's definitely better than most of the self-help books i've read. while i don't entirely agree with everything the author writes (admittedly a lot of their advice comes off as preachy and fearmongering), there are a quite a few pieces of advice that r quite useful (memento vivi, present bias, growth mindsets, + the career advice imo) anw here's to my twenties! and to deciding my life right now :3

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zubayr @zubayr
5 stars
Mar 28, 2023

I gave this to myself as my 23rd birthday gift. I am so glad I found this book in my early twenties. I feel like having this knowledge and with the right effort being able to apply this knowledge will make me 10 steps ahead of other twentysomethings and most of all, 100% closer to my own goals.

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Bouke van der Bijl@bouk
5 stars
Mar 1, 2023

The title is quite cheesy, but I found this an insightful book. The author (a therapist) goes through a series of anxieties that she sees twentysomethings have, where most of them boil down to people not really taking their life seriously and feeling like it's fine to just sleepwalk they way through their twenties, not considering what they want out of life or how they want their next decades to be. This leads to regrets, where people at thirty need to start taking their career and family life seriously all of a sudden and failing at it. The book is definitely aimed at people who foresee themselves having a normie life at some point, so if that's not the path you want then it might not apply to your. But if not that, you need to consider what you want your life to look like instead, and what steps you have to take to get there. Because if you don't then life will just happen to you, time will pass, and you might regret where you end up.

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Mitul Shah@ms
3.5 stars
Feb 3, 2023

I recommended this book to people before I even read it, but honestly it's okay. Maybe it's because where I am in my life, but the part I strongest resonated with was love. I found pieces of myself in each of the people mentioned, and it was nice to build a stronger understanding of where I potentially am going wrong.

Whereas, things about career and mindfulness seemed rather white-collar & westernized.

I'd still recommend a skim! Esp if you're feeling stuck in your twenties, no doubt this book will help you prioritize the more important things before it's too late.

+2
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Anna Cordero@annagmc
5 stars
Jan 26, 2023

This is book is something I think everyone should read especially if your 20 something year old. Everyone can take at least one thing from this book. It made me personally figure out a few things. Honestly probably life changing my

+4
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Jowanza Joseph@josep2
4 stars
Jan 20, 2023

Solid read for anyone in there early to mid 20's. It gives you a good perspective on which philosophies are a waste of time and which ones will lead you to happiness.

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Ivy X@poisonivayy
4 stars
Jan 10, 2023

3.5-4 rating - very realistic book about setting the foundation/deciding on my life now. The anecdotes got a bit tiring toward the end but overall was enjoyable and it was interesting hearing about the different lives these characters led. Quotes: -We are led to believe the twentysomething years don’t matter, yet, with the glamorization of and near obsession with the twenties, there is little to remind us that anything else ever will. This causes too many men and women to squander the most transformative years of their adult lives, only to pay the price in decades to come. -Uncertainty makes people anxious, and distraction is the twenty-first century opiate of the masses. - Many twentysomethings assume life will come together quickly after thirty, and maybe it will. But it is still going to be a different life. We imagine that if nothing happens in our twenties then everything is still possible in our thirties. We think that by avoiding decisions now, we keep all. -“But something better doesn’t just come along. One good piece of capital is how you get to better,” I said. -Yes is how you get your first job, and your next job, and your spouse, and even your kids. Even if it’s a bit edgy, a bit out of your comfort zone, saying yes means you will do something new, meet someone new, and make a difference. —Eric Schmidt, executive chairman of Google -The urban tribe may bring us soup when we are sick, but it is the people we hardly know—those who never make it into our tribe—who will swiftly and dramatically change our lives for the better. -In the twenty-first century, careers and lives don’t roll off an assembly line. We have to put together the pieces ourselves -As a twentysomething, life is still more about potential than proof. Those who can tell a good story about who they are and what they want leap over those who can’t. -Above all else in my life, I feared being ordinary. Now I guess you could say I had a revelation of the day-to-day. I finally got it there’s a reason everybody in the world lives this way—or at least starts out this way—because this is how it’s done. - Psychiatrist and Holocaust survivor Viktor Frankl describes our attitudes and reactions as being the last of our human freedoms. Danielle may not have had control over every situation at work, but she could control how she interpreted them and how she reacted to them. She could get out of her amygdala and put her frontal lobe to work -For work success to lead to confidence, the job has to be challenging and it must require effort. It has to be done without too much help. And it cannot go well every single day. A long run of easy successes creates a sort of fragile confidence, the kind that is shattered when the first failure comes along. A more resilient confidence comes from succeeding—and from surviving some failures -You are deciding your life right now.

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Julia@juliah
4.5 stars
Oct 15, 2022

In The Defining Decade, Jay argues that 30 is not the new 20 and that one's twenties are definitely not to be wasted. I like that Jay isn't afraid to call it as she sees it, and she presents her case in a logical and well-organized, yet still conversational, way. The book contains a healthy mix of research and client anecdotes in support of her argument. The discussion questions included also compliment the book nicely and spark deep thought/conversation. My only criticism is that the advice given is a bit more broad/abstract than the description would lead you to believe.

+4
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Eric@en
5 stars
Aug 13, 2022

I'm so glad I read this as a 22 year old. Heaven knows I'd have stumbled through all the hurdles that come with the 20s. Thanks Dr. Jay

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Alex bell@redlion8
4 stars
Aug 13, 2022

As someone in my early 20s it offered some great takeaways. I found some sections of the book less relevant personally, however it could offer good insight to others.

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Rebecca@bexx
3 stars
Jan 16, 2022

3.5

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Femke@motregen
2 stars
Jan 6, 2022

I don't think I'm part of the extremely specific target audience.

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Cindy@cindyy
3 stars
Dec 15, 2021

After seeing this book pop up on my Goodreads feed for years, I'm glad I finally picked it up after overhearing two peers chatting about it during a longer weekend car ride. There are certainly parts where I felt the author was too prescriptive on what constituted a "successful" and "respectable" life. The case studies presented were difficult for me to relate to due to what I'm guessing is difference in background. Despite my distaste for some of the content and opinions in the book, I really value the experience I had reading this book since it forced me think more longterm than I ever have. In my personal experience, the exercise of thinking longterm helped me tackle the immediate & myopic concerns I had over relationships and my career by forcing me to consider these issues from a more macro perspective. My biggest takeaway after reading this book was: treat your life goals like you would financial ones. If you wish to have a net-worth of X dollars at Y age, it makes sense to work backwards and figure out how much you should make the years leading up to turning Y age and how much you should budget regularly. Similarly, if you have goals of having accomplished goal Z by Y age, it makes sense to work backwards and consider the milestones you'd want to hit prior to turning Y age in order to position yourself favorably for accomplishing your goals.

Highlights

Photo of kata
kata@katacaramel

While personality similarity can help the years run smoothly, any two people will be different in some way or another. How a person responds to these differences can be more important than the differences themselves. To a person who runs high in Neuroticism, differences are seen in a negative light. Anxiety and judgments about these differences then lead to criticism and contempt, two leading relationship killers.

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𝓬𝓱𝓮𝓻𝓲𝓮@caffeineand

These critical periods are windows of opportunity when learning happens quickly. Afterward, things are not so easy. The twenties are that critical period of adulthood. These are the years when it will be easiest to start the lives we want. And no matter what we do, the twenties are an inflection point—the great reorganization—a time when the experiences we have disproportionately influence the adult lives we will lead.

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𝓬𝓱𝓮𝓻𝓲𝓮@caffeineand

...while most therapists would agree with Socrates that "the unexamined life is not worth living", a lesser-known quote by American psychologist Sheldon Kopp might be more important here: "The unlived life is not worth examining."

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Mitul Shah@ms

The future isn’t written in the stars. There are no guarantees. So claim your adulthood. Be intentional. Get to work. Pick your family. Do the math. Make your own certainty. Don’t be defined by what you didn’t know or didn’t do. You are deciding your life right now.

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Mitul Shah@ms

When Danielle called her mother, she was doing what psychologists call “borrowing an ego.” She was reaching out in a moment of need and letting someone else’s frontal lobe do the work. We all need to do that sometimes, but if we externalize our distress too much, we don’t learn to handle bad days on our own. We don’t practice soothing ourselves just when our brains are in the best position to pick up new skills. We don’t learn how to calm ourselves down, and this in and of itself undermines confidence.

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Mitul Shah@ms

They were fooled into thinking they were compatible because they had many plain-sight commonalities. They felt confused as their dissimilar personalities continually clashed.

Photo of Mitul Shah
Mitul Shah@ms

I think he knew that making a choice about something is when the real uncertainty begins. The more terrifying uncertainty is wanting something but not knowing how to get it. It is working toward something even though there is no sure thing.