When Amazon's categories become too deeply nested, they create new categories in the top level. However, because they have thousands of associates with links on external web sites, they retain the "old" categories to preserve these external links. This results in confusing duplicate categories. The old categories generally are not as well maintained as the new ones, so we're redirecting our search to the newer ones.
You will find new top-level categories for Law, Medicine and Science. You will also find considerable duplication and turmoil in Business Management and Education