Faceting provides a way to drill down data by categories. It allows a user to refine a search by concatenating new categories to narrow down a search to the desired results. A useful feature in faceting is that you can preview the total hits with each category values before selecting it. The faceted search method can be used in conjunction with a text search, so it's okay for users to do a text search in addition to a faceted search at any point. In many search applications where data can be systematically categorized, such as product inventory where you have product categories, types, availability, and so on, faceting offers a convenient way for users to refine their searches. A notable benefit of faceting is that the user will never hit a zero results page because you can only drill down with in the available category values.

Let's look at an example for a fictional online bookstore; we will categorize books by subject and author. In the following figure, note that we...