Open Access (OA) content – that is, scholarly content that is freely available to read without registration or payment – is most often thought of in relation to journals and articles, but a healthy market for monographs exists, as well. For various reasons, publishing and tracking OA monographs is both simpler and more complex than working with OA journals. OA monographs may be available online for free yet also have a print version. Collection development librarians can choose to buy print copies of particularly relevant titles, or they can simply add bibliographic records for these titles to their library catalogs or discovery layers, and then direct patrons to online versions of the resources. But finding and tracking those OA titles is a significant challenge, and even the definition of an online monograph can be a bit tricky. The Directory of Open Access Books (DOAB), at DOABooks.org, is here to help, somewhat. With many caveats, it is a tool that many collection development librarians, and some individual researchers, can use to their advantage....