Whenever I'm scanning through my library and see a book I know I want to read soon, I like moving it to Marvin's reading list - I use it as a "what to read next" bin.
Your reading list appears as a smart collection (one that comes built into M). You can see the reading list collection in your library organiser - tap the book icon in the top toolbar.
I've written
a tutorial about how to manage your reading list here.