More seriously, if the topic is of interest to you, I recommend Tanenbaum's book on Distributed Systems. In particular, the chapter 4 explains the rationale behind vector, or logical, clocks using very down-to-earth examples. I did not realize how time synchronization could be such a pain before reading it.

More generally, Tanenbaum's books are always of really high quality. There are maybe slightly outdated, but if you are looking to learn about the fundamentals - it is a safe bet.