The quality of his literary allusions however makes his writing distinctive. These allusions set his work apart from the books cranked out in the "fiction factories" of the day. Great authors alluded to in Alger's boys' book include Shakespeare, Milton, Longfellow, Cicero, Horace, Alexander Pope, Joseph Addison, and dozens of others. The Bible is referenced in more than half of his works. These allusions reveal Alger's knowledge of literature and "enhance the literary quality of his work".