Part of the Twenty Books in Twenty Days series.
I lent “Peopleware” [affiliate link] to a friend at some point but never got it back. I supposed they valued it as much as I do. I should probably buy the newer edition at some point.
I’m not sure if this book was the epiphany or it just happened around the same time, but at worst it was a major influence. The epiphany was that the really hard challenges in computer science were not the technical ones but the ones around people. It doesn’t mean that it’s not valuable to work on technical problems or solve them. But the challenges organising and getting people to communicate and work together effectively and build the right thing (rather than the interesting thing that we want to build) are also important, possibly more important.