Chock full of details. Not an easy read,but ultimately rewarding. Must information is obscure to a non-British reader, but the author manages to provide sufficient, although limited, detail to help those of us from across the pond to understand. There are many assumptions in the book that he is writing for (and he clearly is) a British-based audience. Lots of really good footnotes. Wish there had been more pictures of Prime Ministers and a list of the years they were in office. Just not info that I can readily retrive from my stored knowledge while reading! Hpwever, I do look forward to reading his other books. ( )

At long last, I must concede defeat to the behemoth that is The Defence of the Realm. I first started in August 2010 when it came in for me at the library, didn't finish it, eventually bought the paperback in November because I figured then I could take as long as I wanted... and I've been reading it in fits and starts ever since. I've kept it out on my bedside table since January in hopes of finishing it eventually, but sadly I do not think that is likely. I'll put it back on the shelf and perhaps someday I'll muster up the strength to read the rest.

But don't let me make you think that this is a bad book. Far from it. It is almost too good at what it does -- provide information about the history of MI5. There are so many tidbits and fun facts and dry-witted asides crammed into each page that reading a whole chapter leaves your eyes gasping for air (if that makes any sense). The best parts for me were the bits up to and including the Second World War, then my interest gradually declined until I reached the Thatcher years, at which point I decided to stop. Perhaps the 1980s are too recent history for me to read about.

Anyway if you're interested in the history of MI5, you definitely want to read at least the first half of this book. The second half I would qualify as "your mileage may vary". And be sure to pace yourself. It's a lot to absorb. ( )

An exhaustive and intriguing history of MI5 for which the author was given extensive access to the agency's archives.
I found it fascinating but was often almost overwhelmed by the extraordinary amount of detail that was offered up.
However, I am very glad that I read it and would definitely recommend it to anyone else interested in this field. ( )

This is a scrupulously well researched account of the history of the Security Service MI5 and the operations in which it has been involved. The author has been given access to the great majority of historical files, while forming his own conclusions about the significance of their contents. Inevitably coverage of some recent events is less thorough due to current national security requirements and the need to protect active sources, but is still insightful and sober in its conclusions. The book will not of course satisfy conspiracy theorists of one stripe or another, but the author's judgements seem shrewd and pretty balanced to me, pointing out intelligence successes (e.g. the Double Cross turning of German agents in WWII, or the tracking down and surveillance of Islamic ricin and homemade bomb-making plotters) and failures such as the slowness in identifying the Cambridge spy ring, the over-estimation of the strength of the KGB's analysis of the intelligence they acquired from the West and more recently the relative slowness in the 1990s of perceiving the worldwide reach of Islamic terror plots. The book clearly shows the insubstantial nature of most intelligence and the difficulty of assessing its reliability, points often lost on politicians and the general public who desire certainty and clearcut information.

Finally, one aspect of the book's structure was a little less than helpful, that is the fact that each major section, e.g. WWII, early Cold War, etc. began with a chapter covering how MI5 evolved during that era, before the other chapters giving the detail. This led to a slight confusion on timing in some places and some duplication of material. Usefully, there is a concluding chapter detailing the main points covered in the text. The index could have been more thorough. ( )

Absolutely superb, very interesting, although this was taken as an overview, I found it comprehensive and relatively non sparing of criticism with regards to the controversies surrounding the security service. An excellent read for anyone interested in the subject ( )