Warning: This is half ranting.

I've been sending out a book for several months now, all three publishers I've sent to have rejected it.

I'm wondering if it's because I don't have any other books in the market to compare it too. They always tell you never to say that, but I swear on a stack of Bibles that there has never been a book based on the cat breed Egyptian Mau. Never, not once in the history of writing.

There have been lost of books on the Goddess Bastet, that is supposedly a Mau, and books on Egypt and general cat books that Maus are briefly discussed in - but nothing has gone in depth about the breed more than 100 words.

Does that make it look like I haven't done the proper research? I have figures for market research on people who would be interested in the book & I can back up that I'm more than qualified to write the book, but I get the feeling that the no other book thing is killing me with the publishers. Does anyone have any advice of how to handle that section on a proposal?