Like a series of 6 books that I recently found 1/3/4/6 of in the book sale room at the public library. The library didn't have any of the series in its catalog (these didn't appear to be ex-library-books anyways), and Barnes & Noble's online system didn't recognise any of them either.
And of course this appears to be one of those series where you really need to read them in order, it looks like they might as well be one big book split up into 6 smaller books as far as I can tell.
Ended up grabbing books 2 and 5 off eBay earlier though, same publisher and printing as the rest I already have even. Better condition than the ones I have too, the ones I already have are a bit beat up and the spines of the covers are flaking apart a bit.
(The series of books is called the "Spellsinger" series, if anyone's curious.)