Each course is different-some courses have prerequisites and others don't. The 100 level courses tend not to have any prerequisites. Subsequent levels such as the 101 and 102 are typically dependent upon the 100 level.
Generally, courses are designed to be self-contained, which means you do not need any additional external references. All the required academic materials will be provided during the course within your browser.
Some courses may list additional resources on their course description pages. These are suggestions, typically offered as additional references and reading materials, and not required to complete the course.
These optional additional materials often incur an additional cost, so check carefully the information provided including any links it may include.
There are some publications the University highly recommends and these are part of the university owned publication library, purchasable directly from the University and authorized distributors.