World of Books is British online second-hand book retailer. It formerly traded under the names Wob, Ziffit and Shopiago. As of 2018 it was the United Kingdom's largest. The company buys unsold used books, mostly from British charity shops. The books are resold either to consumers through Wob's website and online, or wholesale to recyclers, with about 80% of the books going to recycling. It was certified as a B Corporation in 2019.