I've enjoyed Lewis's books, but I also noticed this about his unfaltering defense of Aleynikov. In one passage that stuck out to me, Lewis argued that Aleynikov was not guilty of taking anything important as Aleynikov claimed not to have taken any code related to specific strategies, only that code related to infrastructure, which arguably is the most important code that he could have taken. In other passages, Lewis used Aleynikov's defense, that he not only wanted to contribute to open source efforts, but that some of the Goldman Sachs code used open source code, so it should have been okay to take, as if high frequency trading infrastructure code was just floating around in the open source world in the early 2010s.
It wasn't the only issue with the book. Lewis also didn't seem to understand the dynamics of national best bid and offer, and that if a large market order was submitted, it will not be executed at the original nbbo necessarily because of nefarious activity, but because there are not enough bids or offers at the original nbbo to execute the buy or sell for every order at the original nbbo. So much of the book hinges on a misunderstanding of this idea. There is also no discussion of the fact that spreads and liquidity used to be worse prior to electronic market makers. Instead there's this idea that market makers are competing with institutional investors submitting large orders, when really, they are competing with other market markers/liquidity providers, such as how Goldman Sachs e-trading(where Aleynikov left) would have been competing with Teza Technologies (where Aleynikov was invited to). I think that either Brad Katsuyama, who seems to have fed much of the electronic trading related information to Lewis, was misled himself or was possibly intentionally misleading Lewis.