The Millennium's End GM's Companion is, bar none, the best GM's guide out there. This should be required reading for anyone who wants to run a Modern game, and any other genre as well. The intial chapter is condensed nugget after nugget of solid advice on how to run a game so the pacing doesn't drag, the NPCs are original and yet believeable, and the storylines are thought-provoking and attention getting. The maps themselves are worth price of the book, including such hard-to-find areas as a corporate compound and a tenement building. The section on computer hacking and piracy is simple and yet complete, unlike so many modern and cyberpunk lines. Add to that the NPCs and adventures, and it's a combination that's impossible to beat. Here's how good it is: WOTC hired the author to run the D20 Modern line. The only down side is that the book is somewhat dated, as it was published in the mid-1990s. However, the core concepts are timeless.
[5 of 5 Stars!]