My ds9 is also a reluctant book-selector, not sure why. Once he is hooked on a book or series however, he just devours them.
I will pick books and try to get him interested by having him try one chapter or reading a bit out loud.
My ds was also keenly interested in books with pictures, still is, frankly. We had an intermediate phase between picture books and chapter books where he was reading a lot of manga, and other books that are like comic books, captain underpants (franny k. stein is a good one like this, lots of pictures, but more appealing to girls, funny, etc.). Few words on a page, but lots more pages!!
I think lots of words on a page were sort of daunting to my ds at the time.
