The Jack the Ripper A to Z Author:Paul Begg, Martin Fido, Keith Skinner Compiled in encyclopaedic format, this book provides a comprehensive guide to the Jack the Ripper mystery.
Excellent background on Jack the Ripper and all the combined theories; however, slightly dated due to recent "changes" in the Ripper universe. Since I don't BUY the new theories, I still find this a good, up to date source for a Ripperologist.