I've been entering my collection of books into Delicious Library, and although I find many of the barcodes for my books are no longer valid (they must recycle the barcodes according a scheme best understood by whatever authority is responsible for barcodes) but I have been comforted knowing the ISBN has always been sacrosanct... until now. I'm shocked to find that
Would any of the real librarians on my friends list be able to shed any light on this? Are publishers allowed to recycle ISBNs if they reprint a book as part of an anthology? I have seen reprintings share the same ISBN but never a whole new book.