I recommend the book "The Art of Writing Great Lyrics" by Pam Oland.
( http://www.pamoland.com/art_of_writing_great_lyrics.html)

Her style of lyric writing (Top 40 pop) is not for me, but her style of book-writing I found excellent, entertaining, and very illuminating.

- -ken

I didn't think such a book existed :-)
Did it help you? I'll have a look at it..

Thanks!

Julien