Ask HN: Good (computer) networking books?

Hacker News,

I have a fairly decent ad hoc knowledge of various network protocols which I would really like to coalesce into a thorough understanding of the common implementations of at least layer 4 and down in the OSI model. Is there a concise, thorough, and clear book (or group of books) that I could read to help me attain this goal? I'd consider something with the writing style of K&R to be ideal.