Jeff Ladd explains over at PhotoEye, why, what and how Errata Editions came to be:

“It was in 2004 after Martin Parr and Gerry Badger’s The Photobook: A History Volumes I and II were published that I realized not only the huge scope in the array of photobooks (two-thirds of their choices I hadn’t even heard of) but how elusive most were. Nearly 90% of what had been referenced as the “most important” photobooks are out of print and really only accessible to a few wealthy collectors or through research libraries. As a photography teacher, the idea that a young photographer just learning their craft couldn’t, without great effort or expense, experience what came before them was very disturbing to me. It begged the question of consequence; what if the greatest literature or poetry was not available for young writers to be informed by? That seemed to be the current state of the history of photobooks.”

[My bolding]