Interesting side note: Here's a link to an Amazon review of _Dark Pools_. The review claims the name Brad Katsuyama and opens the review with "As an insider in the world of electronic trading..."
I'm liking it a lot so far; it's written by an author who clearly thinks HFT is sinister, but who also seems to think the code behind it is really cool. (Maybe I'm biased, because that describes me pretty well too.)
I quite like Dark Pools even with the obvious bias. I will say that occasionally it gets technical aspects of things completely wrong, but that is pretty easy to do.
Also, as with any discussion about HFT look into the people who are making accusations against it. Most of the time they are ex execution traders made redundant by HFT or failed at HFT themselves.
Basically, I really enjoyed the history part of the book and found the expose part riddled with mistakes, obvious biases and vague terms that could be interpreted in many different ways.