Apogee Space Books had a booth at ISDC, and of course I couldn't resist buying a few space books, especially from the $10 bargain rack, including NASA mission reports on Apollo 11 (2 volumes) and Deep Space (outer solar system probes from Pioneer 10 to Cassini), plus a volume on women astronauts for my outreach collection.
But the most surprising find was a new book by Wernher Von Braun, Project Mars: A Technical Tale. Not exactly new, but a never-before-published SF novel about a voyage to Mars, written in 1949. I've just started reading it, and while the prose is a bit old fashioned, and the technical details figure very prominently, it looks like a pretty decent story of a huge Mars expedition.
The story takes place in the 1980's (30+ years in the future from 1949, following several more world wars and the establishment of an effective world government). The book includes a technical appendix which shows the calculations and diagrams that Von Braun used to make sure that the story was technically accurate, to the level of knowledge of Mars and space technology in 1949. It's surprisingly modern in many respects. The book includes a nice selection of color plates of Mars expedition paintings by Chesley Bonestell.There's a description of the book by Von Braun himself here.