/de-vᵊl bu̇k/
n. 'The Design and Implementation of the 4.3BSD UNIX Operating System', by Samuel J. Leffler, Marshall Kirk McKusick, Michael J. Karels, and John S. Quarterman (Addison-Wesley Publishers, 1989) -- the standard reference book on the internals of BSD UNIX. So called because the cover has a picture depicting a little devil (a visual play on daemon) in sneakers, holding a pitchfork (referring to one of the characteristic features of UNIX, the fork(2) system call).