Wool is by Hugh Howey. In the summer of 2011, Wool was released as a standalone story with little thought that it would ever become so popular. It soon took on a life of its own, and reviewers clamored for more. The next four books were released to satisfy this demand, each one growing in size. Wool 5 is 250 pages long in print. All five books have now been collected in an Omnibus edition, but they were always meant to be read individually.