All are easy to access and engage with, though they're not coffee table picture books, they're books that inspire and inform. The list isn't comprehensive and by no means definitive but each of these books I return to regularly and I wouldn't be without.
None are dry or stale and each invites us to think differently about photography in one way or another.
"The Ongoing Moment" by Geoff Dyer (ISBN: 0349120110 / 0-349-12011-0)
"On being a Photographer" David Hurn and Bill Jay (ISBN: 1888803061 / 1-888803-06-1)
"Image Makers Image Takers" by Anne-Celine Jaeger (ISBN: 0500286620 / 0-500-28662-0)
"Conversations with Contemporary Photographers" Umbrage (ISBN: 1884167489 / 1-884167-48-9)
"Why People Photograph" by Robert Adams (ISBN: 0893816035 / 0-89381-603-5)
"Beauty in Photography" by Robert Adams (ISBN: 0893813680 / 0-89381-368-0)
"The Education of a Photographer" by Charles H. Traub, Steven Heller and Adam B. Bell (ISBN: 158115450X / 1-58115-450-X)
"The Nature of Photographs" by Stephen Shore (ISBN: 071484585X / 0-7148-4585-X)
"After Photography" by Fred Ritchin (ISBN: 0393050246 / 0-393-05024-6)
"Photography and the Crisis of Looking" by Chris Townsend (ISBN: 379131940X / 3-7913-1940-X)