The first thing to note is that the publisher's description makes this book sound as if it is very different to what it actually is. If you are looking for a story of beastly Germans torturing plucky Brits, and plucky Brits facing the worst deprivations and oppression of the concentration camp system, you will not get it. What this is is Captain Payne Best's account of his really rather comfortable if solitary confinement in the VIP section of Sachsenhausen (bet you didnt know there was a VIP section, did you?). It will also by the way not give you the full story of the Venlo incident - that is still under the Official Secrets Act and the "incident" itself only appears briefly and in a form amenable to not breaching that act in a few pages at the beginning, and in Nigel Jones' excellent Introduction.
Now, this does not mean that it is not fascinating - it is. Frankly if you have any interest in how a concentration camp was run, and what sort of people ran it, this may well be seen as an invaluable book, written as it is by an incarcerated Brit, who made close friends with many of his guards and who absolutely buys into the "following orders" defence, because he sees it as an intrinsic part of the (in his view naturally subservient) German character.
But the book is very uncomfortable indeed on (at least) two fronts. First (putting the racial "defence" of the German guards and officers aside) it does rather tend to support the view that "there but for the grace of God" go we, as potential concentration camp guards. His contacts in the SS were clearly fairly ordinary people prone to be charming and considerate hosts to a prisoner who they liked and respected; but they were also capable of treating others (no less worthy or well educated in many cases) with unspeakable cruelty; would we really do any better? Secondly, although one has to have enormous sympathy and a degree of admiration for Capt Payne Best (who clearly did cope with 5 years almost solitary confinement excellently) it is profoundly disconcerting that he found so many people who later were proved to have done such terrible things to be really nice chaps; and still more disconcerting is it to find that while lodged in comfort and with an excess of supplies, he used his excess not to pass on to the people in the main camp who he well knew were undersupplied, but rather to bribing his own guards, to ensure that they would do whatever he wanted.
So - an inspiring book? No. A nice book? Also no. But interesting, and worth reading - oh yes indeed!