This book constitutes the thoroughly refereed and peer-reviewed outcome of the Formal Methods and Testing (FORTEST) network - formed as a network established under UK EPSRC funding that investigated the relationships between formal (and semi-formal) methods and software testing - now being a subject group of two BCS Special Interest Groups: Formal Aspects of Computing Science (BCS FACS) and Special Interest Group in Software Testing (BCS SIGIST). Each of the 12 chapters in this book describes a way in which the study of formal methods and software testing can be combined in a manner that brings the benefits of formal methods (e.g., precision, clarity, provability) with the advantages of testing (e.g., scalability, generality, applicability).