The difference between the Reference Section and the Main Stacks (or Main Collection) is primarily the types of books you'll find in each. The reference section is made up of what we call reference books - dictionaries, encyclopedias, handbooks, atlases, etc. containing short articles that provide background information or basic facts about certain topics. The main stacks house everything else, generally full books devoted to a single topic or subject area.
Here are two examples to show the main differences:
1) This is an encyclopedia related to film studies. Within it you'll find shorter articles about every important aspect of film. Notice the location is Centennial Hall Reference Collection.
2) On the other hand, this item is a book specifically about Italian Film. This will give a deeper analysis of Italian Film than you would find in the encyclopedia above. Notice this item is located in Centennial Hall Main Collection.
