A former student starting a solo trademark and copyright practice recently asked for recommendations for her library. 

I'll share my recommendations here and invite comments for additions for the Essential Library.

1.  The leading and indispensible treatise for practicing trademark law is McCarthy on Trademarks and Unfair Competition by J. Thomas McCarthy.  The principal treatise for copyright law is Nimmer on Copyrights by Melville B and David Nimmer.  Both are multi-volumes, updated on a regular basis.
 
2.  You also need the rules and relevant statutes, including the U.S.P.T.O. Rules of Practice, the the TMEP, (Trademark Manual of Examining Procedures); ...   more »