There are a lot of differences in the TV show and the books. Neither one is better. AJ read the Immortal Instruments because of the TV series. Both are good in their own rights.
I figured I’d share an extra scene outside of the books that Cassie wrote. Magnus and Alec’s first off ‘screen’ kiss. We don’t see them kiss till just before a big battle scene when they are giving downworlder a rune to help connect them to a shadowhunter to fight this big battle. I won’t say more cause if you’ve not read it I don’t wan to leave you with omg thanks for ruining it.
Anyway. Here is Kissed by Cassandra Clare.
The image above is one of the best scenes in the whole series of books. I will not say anything about it, but it was a very happy happy moment. It was done by xiannu studio over at Deviant art.