Years ago, in 2004, I ran my first project as a team-lead. We created a small transactional site for a TV-show, some type of lottery, and we knew that we would have a massive amount of traffic on the evening of the broadcast.
It was right around this time that I read this book, and it had some great info about multi-threading and scalability.
When the day of the TV show came, all was well and the server held up beautifully. A few days later we heard that the government had stopped the lottery from functioning since it turned out to break certain regulations. So there was no winner in the lottery but... my first high-profile project worked.
I'm sure it's dated now, but at the time it was a great read.