I think the book Gilmour was mentioning is Cliff Jones' "Another Brick In The Wall".
A good book for a present would be one of the following:
Storm Thorgerson "Mind Over Matter" A wonderful book on Floyd cover art with interesting comments by Storm.
Glenn Povey/Ian Russell ""Pink Floyd In The Flesh (the complete performance history)" Another excellent book documenting the history of their concerts.
Nicholas Schaffner "Saucerful Of Secrets" Excellent biography of the band (and probably the less expensive of these three
)