Sometimes, there are books that talk about love stories between two people of the same gender (i.e. two boys or two girls who love each other). But a long time ago, when people didn't understand or accept this kind of love, some books like those were kept hidden or thrown away.
Nowadays, some of those books are hard to find, and people call them "lost gay novels." But sometimes, people can find old copies of those books in forgotten bookstores or libraries. When people find them, they can share them with others who want to read about love stories that are different from what they usually see in other books.