Okay, so I picked this up at the library the other day because it looked interesting. I nearly gave up part way through (it didn't have quite as much action as I was hoping for) but didn't because the library was closed and I hadn't really anything else to read.
It's quite a fun idea. Also somewhat complicated. The main character is talking in first person and is a thief who writes books 'pretending' to be a thief. There might be another layer of pretending to be a thief in there, somewhere, but I'm pretty sure I got them all. Just to make life a little more unusual, said thief (as in, the main character of the actual book, rather than the main character occaisionally mentioned in the book within the book) has early-onset arthritis.
The main character is pretty fun, as are the various characters in the somewhat eccentric bookshop. The plot is pretty good too. I think it was more of a personal taste issue--I suspect I would've rather read the book within the book with implausible action scenes and so on--but I did find it a little slow-going in parts.
In conclusion: an interesting idea, a fairly good book. I'll probably read the others, if I spot them (especially as I seem to be having one of my periodic running out of interesting things to read issues), but it's not competing to go on my list of favourites.