It's not on the NASA site but the book is also readily available online in the original Russian, for those who are into that sort of thing.
Same here -- it's absolutely fascinating to see the space race from the other side, as well as seeing Soviet impressions of the Apollo program and the Cold War. Highly recommended.
(on the downside, Chertok really likes pausing the narrative to map out the exact bureaucratic flow-chart of the different agencies and departments involved in rocket development, which is pretty tedious, but I've found I can just skim those sections without losing the ability to understand the rest of the story.)