Why can you not read American girl books online?

You can read books online. You just have to do it legally. Books that are in the public domain, meaning they have no copyrights attached to them, can be read for free at sites such as WikiSource and Project Gutenberg.

Newer books, such as the Twilight series, cannot be read for free legally, but most of them can be legally purchased from reputable dealers that have rights to sell them. Some of these sites include Books and Board and eBooks. Certain sites such as Amazon also sell them, but require the purchaser to have a certain type of electronic reader.

Downloading copyrighted materials from torrents is a felony.