Board Thread:Questions and Answers/@comment-187.123.44.47-20140112025249/@comment-5230978-20140116145330

I'm saying to skip Index only manga, 'cause is a poor adapation. As said above there are some added scenes in it and some trivias, but there are only few of them. If you are interested in them then go ahead and read it, but I recommend to do it after reading the rest.

Index and Index II covered the novels from vol 1 to SS1, Railgun and Railgun S from tankobon 1 to chapter 41 (tankobon 7). Anyway, it's best to read all  of them from the beginning, 'cause Index anime cuts a lot from the novel, though not as much as the manga does, and Railgun anime tends to mellow some scenes and is full of cloverfields. Obviously in the Railgun manga the filler episodes and arcs are absent, and there are differences, especially about the timeline, between Index and Railgun animes and the original works.