Determine the value of the books or the amount you'd like to receive. Take them to an appraiser to get an idea, if you are not sure of the value. Research the price of similar items online.
Contact a history museum to see if it is interested in the books. There are history museums all over the country and some of them specialize in wars.
Get in touch with World War II memorabilia collectors. You can search online for collectors of World War II memorabilia or historical books.
Look through classified ads in your newspaper or online. You may find someone seeking antique books or World War II memorabilia. Try Craigslist (craigslist.org) or a website that specializes in antiques.
Contact a bookstore that specializes in rare and antique books. Negotiate a price if the owner is interested in purchasing your collection.
List your German military books on an auction site like eBay (ebay.com). You can set your own price and don't have to sell them for less than what you'd like to receive.
Be patient. It may take a little while to get the value that you'd like for your collection.