Messengers of Deception by Jacques Vallee
The perception deception by David Icke
Not in his image by John Lamb Lash
The murder of reality by Pierre Sabak
Mirage men by Mark Pilkington
The mystery of the crystal skulls by Chris Morton
Cosmos by Carl Sagan
Less incomplete by Sandie Gustus
The Orion Mystery by Robert Bauval & Adrian Gilbert
Technology of the Gods by David Hatcher Childress
The Earth Chronicles Handbook by Zechariah Sitchin
Operation Trojan Horse by John Keel
Humanity's Extraterrestrial Origins by A.D Horn
The genius of the few by Christian O'Brien
Flying Serpents & Dragons by R.A. Boulay
The song of the greys by Nigel Kerner
Chariots of the Gods by Erich Von Daniken
The Sirius mystery by Robert Temple
Many of these books I can attest to. A few I would also recommend : The Gods of Eden by William Bramley, Forbidden Archaeology and Forbidden History by Michael Cremo and Richard Thompson.
Gram Hancock has also done a lot of interesting work.
good list I will make sure and looks for these titles next time I am at the bookstore.