I would also recommend reading "Flash Boys: Not so Fast" (http://www.amazon.com/dp/B00P0QI2M2).

This is a really fun read. Thanks for pointing it out!

Written by a high frequency trader. Are there any third parties that have deeply explored HFT and come out in defense of it?

Sure. Vanguard has the widely publicized view that HFT helps to bring down the cost to retail investors for instance

http://www.ft.com/cms/s/0/ff8c6486-cb37-11e3-ba95-00144feabd...

Are there any other resources you can recommend for learning more about HFT?

For blog post style reading 'yummyfajitas' series on HFT is good:

https://www.chrisstucchio.com/blog/2012/hft_apology.html

For technical books:

- Trading & Exchanges by Harris (a little out of date)

- Algorithmic Trading & DMA by Johnson.

On the narrative non-fiction side Dark Pools is basically it.

Great, thanks!

There are several books which speak about HFT at a high level. If you are curious about the actual mechanics of stock exchanges and (a bit about) how various parties make their money, I wrote a bit about it at http://falconair.github.io/2015/01/05/financial-exchange.htm...