This specially prepared work compromises a living archive of important programming languages, described by the people most instrumental in their creation and development. Drawn from the ACM/SIGPLAN Second History of Programming Languages Conference, this volume, like the earlier book from the first such conference (HOPL), conveys the motivations of the language designers and the reasons why they rejected existing languages and created new ones. The book relates the processes by which different languages evolved, in the words of the individuals active in the languages' development. Most important, participants share insights about influences and decisions, both on choices made and on the many roads not taken. In the book's conclusion, distinguished historians of computing share views about preserving programming language history. . Fourteen chapters cover a broad range of languages in wide use today, as well as lesser known languages that made significant contributions to programming language evolution: C, C++, Smalltalk, Pascal, Ada, Prolog, Lisp, ALGOL 68, FORMAC, CLU, Icon, Forth, Monitors and Concurrent Pascal, and Discrete Simulation Languages. Prominent contributors to the book are Frederick Brooks, Alain Colmerauer, Richard Gabriel, Ralph Griswold, Per Brinch Hansen, Alan Kay, C. H. Lindsey, Barbara Liskov, Richard Nance, Elizabeth Rather, Dennis Ritchie, Jean Sammet, Guy Steele, Bjarne Stroustrup, William Whitaker, and Niklaus Wirth. Together, the conference contributors and the book's editors have put together a volume of interest to researchers, teachers, students, and computing professionals everywhere who are involved in the use or the development of programming languages today.