d20 Modern Role-Playing Game and d20 Modern Menace Manual
Man, I'm a geek. Mind you, I find running modern adventures a lot easier than running fantasy. It all makes so much more sense! Unfortunately, the core rulebook is full of inconsistencies and contradictions. There have been many errata to clarify things. Unfortunately, some of the errata written by different people contradict each other as well... Problems aside, the book is comprehensive ad provides a great role-playing experience.
Now if you'll excuse me, Bobby has some mischievous gnolls to hunt...
