For those interested in the history of tabletop roleplaying game design, Monsters, Aliens, and Holes in Ground is an excellent, near encyclopedic treatment. The author, Stu Horvath, documents major and minor game systems, how they innovated or were influenced by other game systems, and how the systems expanded with settings and adventures. Horvath covers the 1970s through the 2010s and, reading through the entries, chronicles the major changes in design theory from simulation, to forms of nar...
