There are many linguistic books around - in many languages. Although the data about the books are harvested automatically, it is impossible to categorize the books automatically. Therefore, all books are added semi-automatically view the Tools section. Since we can only provide data for book we know about, we allow users to add books themselves. It is only possible to add books that are in the database of one of the 5 Amazon sites - partly because it hard to gather data for other books in a consistent way - and partly because books that Amazon does not list cannot be bought via Amazon - which makes making them available at this site less relevant. The restriction to Amazon servers means a restriction to a limited set of langauges. This restriction is even increased by the fact that we left out Amazon Japan because this site is not Unicode based.
Although uses can add books, they cannot actually edit book data. All data are gathered automatically from the Amazon webserver - in some cases expanded with data harvested from other sites. These data can be wrong or incomplete - in which case it might be good to allow users to manually edit errors. And books that are not in the Amazon database could be added manually as well.
However, manual editing inevitably leads to too much inconsistency - if there are errors in the data, please let us know and we will correct them. But users are only allowed to edit the classification of the books - which is not part of the Amazon database.