While giving a lecture on Paul Elder in 2004, I was asked this question. It’s every bibliographer’s nightmare, of course: failing to record a title.
I am confident that the current online checklist records 99% of Elder’s output; the uncertainty concerns that last one percent. All the earliest records of the bookstore were destroyed in the 1906 earthquake and fire. Many of Elder’s books are quite rare: there are several titles in my collection where—despite all my years of looking—the copy I own is the only one I’ve ever seen. That doesn’t necessarily make them valuable, just rare. There are also plenty of titles I do not own, though not for lack of searching.
There have been only three new discoveries in the last decade, although each has resulted in multiple checklist entries. Those recent additions were:
- in 2009, I found a catalog with ten new titles in the Impression Classics series (checklist 404-413)
- in 2010, I found a catalog that listed five new titles in the Vest Pocket Helps series (checklist 414-418)
- in 2012, I discovered two titles in a hitherto unknown series called the Langham Library of Humour (checklist 419-20)
If you are working from one of the printed checklists, the addenda & corrigenda can be found here.