In any case copies were eventually gathered into collections. Apparently, there were collections of Paul’s letters (cf. 1 Pet 3:16). They were copied into codices, which are similar to modern-day books, with the pages sewn together to form a binding. In this form the documents were easier to read. Leather or scrolls were harder to use because the entire book had to be unrolled to find a passage. Also, papyrus sheets cracked if rolled into a scroll; hence, the flat papyrus pages were sewn into a book.