This is published by Pocket Books and so looks good along side The Watcher's Guide (and presumably TWG2 due out soon). As you would expect from Chris Golden its chock-full of information, trivia and and quotes from the series. UK viewers should be warned though, it details everything up to the end of Series 4 so has considerable spoilers for anyone watching on the BBC.
A little disappointing in its quality - I noticed a few typos, and mis-quotes - but overall an interesting, informative and incredibly detailed synopsis of the monsters of Buffy. As the name suggests it deals exclusively with the 'Bad Guys' of Buffy and takes the reader through history, mythology, legend ....and make-up.
Another must-have for the die-hard Buffy fan!