Like The Mammoth Book of Jack the Ripper this book starts by giving the bare facts of the Ripper-crimes and then offers an overview of some more-or-less serious theories about the identity of Jack the Ripper and the little-and-less serious fictional accounts dealing with him. The difference between those two books is the The Pocket Essential is shorter (mainly because it's not an anthology where various authors offering their opinions but just one author summing up the main points and commenting on it), better written (so much better) and...funnier. Not the first part about the facts, which is quite dry (as it should be) but when it comes to the theories the author already clearly states when he thinks one is rubbish (You didn't have to be famous to be considered a Ripper-supect but it surely helps) and especially the way he rips apart Patricia Cornwells theorie is just delightful. However that is nothing compared to the way he comments on books and movies inspired by Jack the Ripper. I did laugh out loud a couple of times reading that part:The Ripper became the crime and horror writer’s equivalent of the dread ‘dead pet/living pet’ story in sitcoms: something reliable that you could turn to in times of creative hardship. Nowhere is this more apparent than in the countless crime titles in which a serial killer either kills in the same style as the Ripper or is gifted a similar nicknameIf you’ve ever wondered what a horror movie made by a bunch of goths would look like, then I Am the Ripper (2004) might give you an idea. An amateur French cast get killed, come back to life, and get killed again by a hooded figure who may be Death or possibly Skeletor. Exactly how Jack fits into the story may be just the result of an opportunistic retitling for this incomprehensible mess. At one point someone does appear wearing a top hat and a cape but by then our brains had shut down our retinas as a precautionary measure and we knew no more.And if Holmes’ solutions aren’t satisfactory then there have always been others to have a go. Mycroft Holmes, Professor Moriarty, Inspector Lestrade, Irene Adler and even Holmes’ ‘sister’, Charlotte, have all had their own Ripper-hunting stories told. In fact, the only character who doesn’t seem to have tracked the Ripper is Mrs Hudson... Now why would that be? Surely not...I could go on and on about this and basically quote the final third of the book because it's so hillarious (while always taking care only to make fun of crazy people having crazy ideas about Jack the Ripper but not him/his victims or the crimes itself). So overall it does give a good starting-point if you want to know more about Jack the Ripper. The only disadvantage it has to The Mammoth book...is that you have to take Whitehead's word on the ridduculousness of the theories, while in the other books the various Ripperologists are given the possibility to make a fool of themselves all on their own. I still think that I prefer this one as the writing-style does not make me want to scrap my brains out (yeah...and also because of the snark).