Some standards on my bookshelf:
http://www.amazon.com/ultimate-pipe-Richard-Carleton-Hacker/dp/0931253004/ref=sr_1_2?s=books&ie=UTF8&qid=1373464914&sr=1-2
http://www.amazon.com/Book-Pipes-Tobacco-Carl-Ehwa/dp/0394470001/ref=pd_sim_b_1
http://www.amazon.com/Search-Pipe-Dreams-Rick-Newcombe/dp/0966623916/ref=pd_sim_b_3
http://www.amazon.com/The-Pipe-Book-Alfred-Dunhill/dp/1616080493/ref=pd_sim_b_4
http://www.amazon.com/Rare-Smoke-Ultimate-Guide-Collecting/dp/0931253101/ref=sr_1_3?s=books&ie=UTF8&qid=1373464914&sr=1-3
Wow, $60 for used copies! (I paid $20....)
http://www.amazon.com/Confessions-Pipeman-irreverent-todays-pipe-smoking/dp/B0042QREIE/ref=sr_1_3?s=books&ie=UTF8&qid=1373465267&sr=1-3&keywords=gary+schrier