I really enjoyed buying the Grateful Dead Sheet Music Book. It has many songs from the Workingman's Dead/American Beauty Era. It made learning how to play those songs really easy as they had all the Chords and Lyrics...

Before the Internet, it was very difficult to learn songs. Mostly what I would do is play a record for a brief time, write down the words and then move the needle back to get the next lyric... Often, the words were hard to understand... Then I would have to guess what chords were being played... Subtle differences like "What Key the song is in..." were totally impossible to figure out from the record [for me]... So having the Grateful Dead Sheet Music Book was a blessing because the secrets were all revealed! AND! WE got a dozen Interesting Illustrations... 

Link to the... Annotated Grateful Dead Lyrics... a Website with the Words and Possible Meanings of the Songs... 
http://artsites.ucsc.edu/gdead/agdl/