Liburuaren arbola is a travelling exhibition. Designed by Gorka Arrese, it aims to help people understand what books are and why they are important. The exhibition outlines the principal parts of a book: the anatomy of letters, the physiology of text and the biology of books themselves. It also analyses the stakeholders involved in the process: writers, editors, readers and printers, and focuses on Basque literature and the work carried out by publishing houses.