Advanced Search will allow you to use more precise searching if you know exactly what you are looking for. It does not use the same broad Word Search that the Basic Search uses, therefore, more precise search term definitions are required.
There are a number of defaults that are presented when you first bring up the Advanced Search page. However, you can change the type, the comparison and the value for each row of search criteria, you can delete criteria rows to confine the search to one or more row, and you can add rows if you want to add more precision to your search.
Take the mouse and hover over the first section and it will allow you to change the field that is being searched.
The comparison section has an associated list that you can change as well.
Finally the <enter the value> allows you to either type in a value or pick it from a drop down.
As an example, should I want to search for books written either by authors named Jones or authors named Smith, I can easily build an Advanced Search to do so: