She says:
From Jan. to Dec. of 2010 participants will read any type of book, from adult to children, long or short, fiction, nonfiction or even memoir. The only requirement is that it must be about dogs of course. Feel free to post your list below in the comment section, or post a link below to your blog where the list will be posted.
So it doesn't look like there is a certain number. So I'll keep track of dog books I read here.
