1. "A Field Guide to Rock Art Symbols of the Greater Southwest" by Alex Patterson.
2. "Landscape of the Spirits - Hohokam Rock Art at South Mountain Park" by Todd W. Bostwick and Peter Krocek.
The first book is dog-eared indicative of plenty of use (so the tip is confirmed)! Second book just arrived today. Had a chance to briefly flip through a few pages and it looks like a comprehensive, readable, reference to South Mountain.
The site in the Picacho's would be a national monument if it was located on lands other than state trust. Some where in my library is a publication regarding the Picacho Mtn. Petroglyphs. Several miles to the north is a memorial to a AirForce Pilot killed in a crash, impressive memorial.