What's impressive, on first blush, is the range of computing platforms on which Klein's techniques pay off: media players, the Sun Solaris system call interface, a browser-based conference tool, Mac OS X kernel code, and a jail-broken iPhone, to name most of them. It seems so matter-of-fact and effortless, at some points, that all that seems missing are more people to do this same work. The concepts he begins with are simple, the techniques and their attendant logic -- none of it is surprising.

But for all the appearance of ease Klein projects on his subject platforms, it has little to do with an enormous capacity for details or a penetrating genius. These stories reveal instead an adept, persistent researcher who knows his tools and relies on the realities of stack- and library-based software development to create opportunities for him. Klein's real asset is a hunter's stamina, patience, and certitude that his prey is never far off. It simply takes some number of hours, carefully poring over thousands of lines of unremarkable code, to find a hint that turns into a trail that leads to an exploit.

Klein's perseverance and passion for this game are key gifts. A Bug Hunter's Diary is fun to read in part because we tune in at the dramatic turns, if you will, of each story. What deductions Klein gleans from each turn follows logically from his preparation and his methods. What also seems to help is the muted pleasure he gets from his work. He has not met a codebase he didn't like, or so I would guess.

Good, concise narration aside, these accounts won't interest readers with no taste for code review. Those easily put off by a heaping handful of details one has to mind in following the longer entries won't enjoy the ride much either. For the rest, there is something to learn from each example and more than a few valuable insights scattered along each trail. The rewards will add up for any attentive and thoroughgoing reader.

Note: If you're interested in texts that discuss the tools, processes and methods that inform this kind of work, I like Kris Kaspersky's books, Shellcoder's Programming Uncovered and Hacker Disassembling Uncovered. Do Kris a solid and buy them if you like what you see.