George R. R. Martin’s Tuf Voyaging remains sadly out of print, but some small quantity of a relatively recent small-press edition are available directly from the author, autographed.
I made sure to place my order before mentioning this on my blog, just in case. My two paperback copies of the book are both starting to lose pages, and it’s an old favorite.
"I feel obliged to point out that a rather large carnivorous dinosaur has appeared in the corridor behind you, and is presently attempting to sneak up on us. He is not doing a very good job of it."
-- Haviland Tuf, Ecological Engineer