There was a good number of classical books on engineering and software development there. I've found Code Complete 2 and several Martin Fowler's books in Hacker Dojo's library. I've added a few of my own books. A few books I've put on my reading list, but didn't see them again (somebody got to them before me).
Other books were largely outdated. Not many folks would want to read Flickr Hacks (2006) or Programming Windows 3.1 (1992).
- Post a message on Google group, Facebook, Twitter, and such. There are people who love books and know what to do with them. They could take them home, then bring them back to the new Hacker Dojo location.
- There are plenty of ad hoc book exchange cabinets at local coffee shops.
- Public libraries accept book donations. They either add books to their inventory, or sell them.
- Set the book shelves outside. That gives folks some time to browse and pick out valuable ones. That's still a smarter option than a dumpster.
By the way, during the previous move (from Whisman to Fairchild), the library was preserved.