Reserves are held at the Sherman Fairchild Library (SFL). There are two types: open and closed. Open means they are out on the shelves, organized by course, and you can go get them yourself. Closed means they are held behind the ciruclation counter, and you have to ask for them. The borrowing time for both is 3 hours. Returning reserves on time is considered a part of the honor code. The catalog will tell you the location of a reserve and its type.
To access course reserves, go here and click "course reserves" under the search box.
The library can borrow books and purchase articles for you that it does not own or have access to. These services are commonly known as inter-library loan and document delivery. Docuserve is the name of the unit in the Caltech Library which delivers these services, and they are generally free. You must first register with Docuserve before you can use it. You can do that by clicking the log-in link on the left-hand side of this page.