I have most of the Dangerous Weapons series and the French by John Watson is superb.Unfortunately that is not always the case however.This book on the Caro Kann gives nothing on the Short System of the Advance var. which is one of whites most promising continuations.The 3 chapters rehabiliating the 5...Nc6 var. against the Panov Attack are excellent however.The main problem with this series as is also the case with most other opening guides is they have never had the main lines and authors analysis verified for reliability by Fritz or Shredder, or the worlds most powerful engine "Houdini" (free too!)which is World Champion Viswanathan Anand's favorite, according to an interview given on June 10, 2011 for Chessvibes.com with an ELO rating of 3250 or the new Houdini 2 Aquarium Pro with a current CCRL rating of 3347.By doing this you will know what lines are good and which analysis you can rely on at your next tournament. The 3 chapters on the "Botvinnik-Panov Attack" by GM John Emms all pass the "Houdini" verification test with flying colors.Unfortunately the chapters on the Bronstein-Larsen var. 4...Nf6 5...gf6 dont even pass the ECO test (Encyclopedia of Chess Openings at B16, 4th edition) let alone a Houdini verification test and will only work if your opponent never studied MCO 15 or NCO (Nunns Chess Openings). Chapter 2 of this book is entitled "The Charging h Pawn" by Palliser and is a good example of what I am talking about.Here Palliser recommends the following system for black:1.e4 c6 2.d4 d5 3.Nc3 de4 4.Ne4 Nf6 5.Nf6 gf6 6.c3 h5!?He then examines a strong white continuation with 7.Bc4 Nd7 8.Qb3 e6 9.Nf3 Bd6 10.0-0 Nb6 and now at page 49 only mentions 11.Be2! in a footnote stating that after 11...Qc7 12.c4 c5 13.Be3 black should be alright.According to Houdini however after 13.Rd1!! black is struggling since his light squared Bishop has never been activated, making him technically a piece down with white calling all the shots.The line rehabilitating the 2.d3 Kings Indian Attack is also very weak.So you really buy these books at a risk, since at club level rest assured anyone over 1700 will have studied MCO 15 and the other sources mentioned.It boils down to the author of each particular chapter.I still enjoy going through this series however but be aware of what I have had first hand experience in, for example when I have tried the recommendations and terrible analysis from "Dangerous Weapons the Nimzo Indian" (see my review) I got horrible positions and lost many games. So you should always check your favorite lines and especially the analysis, with a powerful engine before using it, otherwise your opponent at the next tournament might unleash a deadly opening that catches you totally unprepared.The Dangerous Weapons series is therefore not without faults, but if you check and verify the mainlines and analysis before using it, the results can be rewarding.