I recently purchased a copy of The Life History and Ecology of the Slider Turtle, by J. Whitfield Gibbons. 1990. Smithsonian Institution Press. 368 pp. ISBN 1-56098-213-6 from The Strand bookstore in NYC. I got a copy that appears brand new for $17.50 (about half price): I purchased it in person and at the time ( 2 weeks ago) they had another copy in identical condition. They also do mail orders.