A local librarian mentioned to me yesterday she was in the process of recommending cuts of $21,000 in periodical acquisitions. Asked how this is being done she told me that one of the inputs is based on scanning the codes on items left out on tables by visitors, which indicates interest in the item. So, if you want you local library to maintain its collection in your area of interest, DON'T RESHELVE ITEMS. Mum may have told you to always return things where they came from, but it doesn't apply in the library. You might want to pull out a few additional genealogy items and leave them out.