Especially in the course of doctoral-level research, you are bound to identify items that would be of use that are not held at U of I. This typically happens if you are "ctiation hopping," i.e., reading one article and searching for the articles it cites, or if you are searching WorldCat or a journal database to see what potential items exist on your topic.
The process of locating journal articles online is illustrated in the "journal articles" tab of this guide.
For books, scores, dissertations, and sometimes recordings, you have several options to obtain these materials.
1. First, search the I-Share catalog to see if the item is held in the state of Illinois. If you find it in the catalog, click on the "Request" button, follow the instructions, and the item will be delivered in about a week.
2. If you cannot locate the item in I-Share, the next step is to complete an InterLibrary Loan (ILL) request. To do this, you need complete bibliographic information about an item--this means author, title, publication information, page numbers (if relevant), etc. If you don't already have this information, search WorldCat, IIPA, or another journal article database until you find the item you are after.
The speed of the ILL process varies depending on several factors--how many libraries own the item and are willing to lend it, how far away the lending library is, etc. So, don't leave this step until the last minute. While you might be surprised with an item that arrives in 3 days, the average turn-around time is 1-2 weeks.