In the last decade, book exchanges, most prominently those registered with the Little Free Library® network, have attracted the interest of researchers and media alike. Very little is known about what types of books are available in these book exchanges and how their collections compare to those in public libraries. To address this gap in knowledge, we selected a random sample of 42 Little Free Libraries across eight Seattle neighborhoods to inventory their contents. We interviewed the stewards about their stocking and weeding practices. Our inventory shows that most of the books available in Little Free Libraries are children’s, mystery, suspense, self-help/health, and scifi/fantasy books published in the last 10–30 years. Neighborhoods in our sample ranged in socioeconomic and racial diversity measures, but there were no significant differences in LFL contents related to those measures. We also compared our inventory to the collections of nearby public library branches and found Little Free Libraries offer a complementary rather than competitive selection scenario: books in LFLs are generally older, with a lesser proportion of children’s books and higher proportion of fiction books.