This book does not emphasize the nature of innovation in software, a topic discussed in other books (Torrisi 1998). A classic but still recommended discussion of the software development process is Brooks (1975). A comprehensive though somewhat dated treatment of the economics of software development is Boehm (1981), and a more modern treatment is Gulledge and Hutzler (1993). For an excellent discussion of the issues attendant to community-based development software, see the April 1999 issue of the Communications of the ACM, which includes an article by O'Reilly (1999). Bass, Clements, and Kazman (1998) and Bosch (2000) provide comprehensive discussions on software architecture.