At 7mo, get squigdy/noisy/touchy-feely board books. "That's not my [dinosaur or whatever]...." series and there are loads of others. When they are teeny, it's just about looking, pointing, discovering and turning pages. Oh, and chewing the edges!
If you feel the need actually to read as such, then you can get board books with a few words in them, and there are of course things like Duck in a Truck etc, which are rhythmic and fun, with great pictures.
the thats not my books are very popular. other early ones my kids liked were 'hooray for fish' 'maisy' 'this is the bear' 'elephant and the bad baby' any of the younger books by Julia Donaldson. sharing a shell is lovely. any rhyming ones are good.
We used to read stories to them from about 6/7 months and books with nice clear colour pictures are great for that. I used to have board books where they could look at them, chew them whatever and then story books which I kept out of reach and we just read to them with them on our knee or when they were lying in the cot so they didn't chew those ones.
if you want ones where you can point things out and talk about things then dorling kindersley do some nice ones with clear photographs of objects, and the Toddlers big book of everything is a lovely book.