The Bookshop Book By Mark Lawrence

Bookshops have always been places where worlds collide. Places where ideas make war, where cultures meet and mate. Frederick 'Red' Archer is hanging on at the edge of society, in the care of the state, when he wanders into the bookshop that will change his life. Rose Penrose is watching the world from the other side of the page, exiled by an act of awful violence, and is now fleeing from story to story whilst searching for her own. The Great Smith has had a hand in both their pasts and an eye on their future. They are tools that he has fashioned for a greater purpose. Tools to be used up and discarded. All that is certain is that a story has them all in its jaws. And that it is about to bite.

This book is a prequel to The Library Trilogy.  It is set in the same expansive universe where books contain living worlds, functioning as a companion or prequel story that expands on the lore and context of the main trilogy.

It can be read as a self-contained standalone story, so you do not need to read it at a specific point in the core trilogy, though readers familiar with the main books will spot extra connections.