One of the basic principles of the library is that we share. We collect information and share it with you, and we share it with other libraries. The whole IU library system shares materials with each other, and that sharing even extends beyond IU. If there is something you want, and we don't own it here in the IU library system, but some other library outside IU does owns it, we can still borrow it. We call this interlibrary loan, or ILL.
The thing about ILL is that it takes time. An ILL request can take a week, or it can take longer. The speed with which ILL materials are sent depend on a number of factors. This is one of the many reasons why it is so important to begin your research early. You need to build in time to allow for ILL materials to be sent to you, if needed. Don't wait until the last minute!