Our DS11 with ASD is not a huge book-lover. Very (very!) capable, but always prefers nonfiction, preferably things with accompanying diagrams, and picking up a book is not his first choice of how to spend free time.
We have gone for high-interest stuff, and indulged the interest in diagrams and images. Lots and lots of science textbooks at all levels in our house. Atlases, books with historical timelines, National Geographic and Discover and Muse magazines, all sorts of things where the images were so compelling or funny that the captions would also be read. D'Aulaire's myths. Asterix comics. Calvin and Hobbes. Pokemon books. DK "illustrated history of this or that" books.
At age 7, it was probably Diary of a Wimpy Kid and Captain Underpants (ugh-- but he read them).
The Horrible Science series are still much loved here, as are all kinds of graphic novels. There are some very good ones about mythology out there. He also did like the "Wrinkle in Time" series, and Harry Potter, and the Rick Riordan books-- it just has to catch him the right way at the right time for him to be interested.
Incidentally, DH was not an avid reader until his 20s but that has not hindered him. Perhaps some people just get there later...
