Just one small error in this deeply researched book to be corrected. Blake’s codename ‘Diomid’ doesn’t mean ‘Diamond’ but is the Russian version of the Greek name Diomedes, as well as the name of a bay near his recruiter’s native Vladivostok. Blake died on Boxing Day last year, making this book uncannily timely. Kuper’s highly readable and multi-layered portrait is largely sympathetic, yet clear-eyed about the human cost of moral stances. Like the naive believer Alden Pyle in Graham Greene’s The Quiet American, Blake’s attempt to save humanity ended up destroying lives.