A HFT's Response to Michael Lewis' Flash Boys
amazon.com
amazon.com
It's written by someone who has actual market understanding and I found it to be a pretty devastating rebuttal to Lewis' book.
Not surprisingly it has a U shaped review curve with people either giving it 5 stars or 1 star much like the beloved book SICP.
If you'd like both sides of the story then I'd recommend reading this, it can be consumed in an evening!