I posted a very heavy cookbook/tome.  It had some water damage and bending of pages from sliding down the bookshelf but the inside was excellent and no writing was in it that I was aware of.  I PM'd the requestor these conditions.  He said to send it anyway, he wanted the book.  He did not mark the book received for almost 1.5 weeks so I sent him a PM to make sure he got it and there was no problem.  Now he is stating the water damage is more than he expected and there is writing throughout the book which I swear there is not.  We hardly used the book.  The water damage was also minimal.  What would you do?

He needs to mark the book received regardless of anything else. Not marking books received is against the rules. He can mark it as RWAP if he wants, and request his credit back from you, but he is REQUIRED to mark it received.

As far as the book you posted ... the thing is that technically, water damage is unpostable even if you messaged him about it.

However, I think it is probably a gray area in regards to cookbooks.

Cookbooks do not have to follow the usual postability rules, as there can be 1. writing of any type, and/or 2. food stains, both inside the book and on the cover. (and as long as you PM the book requestor and disclose the condition, and the requestor accepts it, which you did and he did).

I could certainly see the argument that mild liquid damage is the equivalent of food stains, and thus allowed on cookbooks.

But an argument can be made the other way, as well, as the rules are not clear on that point.

Since he knew about the condition when he accepted the book, I think the correct thing for him to do is to accept the book without requesting his credit back.

This is what I wrote (it's been awhile since I've seen the book but I try to be very accurate when describing to requestors):

I need to let you know this book is about 10 years old and although it hasn't gotten much use, there is some staining on the fore-edge, a couple pages crisped from water and the last 20 pages or so are curled at the bottom corner of the fore-edge due to the book sliding down on the shelf over time. Otherwise the inside pages are in excellent condition. There is no writing. Would you still like this cookbook?

On one hand, he did accept after being told about the water damage, but on the other the water damage itself makes the book unpostable to begin with. He does need to mark it received either way, though he seems like he'll mark it RWaP and I'm imaginging that this will end up needing to be resolved by TPTB.

The weight of the book is irrelevant to whether or not a book is postable.

An unpostable book shouldn't have been posted directly to someone's wishlist but instead to the "unpostable wishlisted books" in the book bazaar thread. Then if someone wanted the book they would have buddied the credit and you could have used "mail to a friend" so the transaction is outside of the system.

The question is whether you adequately descibed the problems of the book or were they worse than you described. It sounds like there were more issues than than described like the writing on the pages as you said "there is no writing;  "a couple of pages" to me sounds like two or three had water damage (were more pages water damaged?); then the "last 20 are curled". If the damage is worse than agreed and you were very specific,  you are in the wrong. Photos the requestor sends can clear this up easily.

The requestor needs to RWAP the book and you can then refund the requestor's credit. You can chalk this up to a learning experience of the posting conditions and stop posting unpostables directly to members and start using the book bazaar.