The simple answer is that you can look by keyword, author, title, or subject. Just type your search terms in the appropriately labeled box and look at whatever results come up. Sounds like Google, only not quite. The more complicated answer is that a library catalog is a database with separate indexes for keyword, author, title, subject, and so on. Unlike the Web, they are structured in such a way that there is only one official way to express a name (personal or geographic), title, or subject. They are also structured in such a way that you do not have to know these official forms before you begin a search, but if you can recognize them, it's a lot easier to make sense of your results and refine your searches.