In addition to covering a history of free and open source, The Daemon, the Gnu, and the Penguin explores how free and open software is changing the world. It is authored by Peter H. Salus, a noted UNIX, open source, and Internet historian and author of A Quarter Century of UNIX and Casting The Net and other books. Salus has interviewed well over a hundred key figures to document the history and background of free and open source software. In his book, Salus reaches back into the early days of computing, showing that even in "pre-UNIX" days there was freely available software, and rapidly moves forward to the Free Software movement of today and what it means for the future, drawing analogies and linkages from various aspects of economics and life.