The Request for Comments or RFC's as they are commonly called are a set of manuals describing how the internet should work.
An example would be an explanation of how POP,HTTP or SMTP functions. An RFC exists to describe how the process should actually be carried out from the initial connection to completion. If the RFC's did not exist it would not be possible to have the internet we have today.
If you are new to computers or are curious as to how the internet operates, reading the RFC's will give you an up close look of every nook and cranny of the internet.
The Requests for Comments (RFC) document series is a set of technical and organizational notes about the Internet (orginally the ARPANET), beginning in 1969. Memos in the RFC series discuss many aspects of computer networking, including protocols, procedures, programs, and concepts, as well as meeting notes, opinions, and sometimes humor. For more information on the history of the RFC series, see "30 years of RFCs".
The official specification documents of the Internet Protocol suite that are defined by the Internet Engineering Task Force (IETF) and the Internet Engineering Steering Group (IESG ) are recorded and published as standards track RFCs. As a result, the RFC publication process plays an important role in the Internet standards process. RFCs must first be published as Internet Drafts.
The RFC Editor is the publisher of the RFCs and is responsible for the final editorial review of the documents. The RFC Editor also maintains a master file of RFCs called the "RFC Index", which can be searched online. For nearly 30 years, The RFC Editor was Jon Postel; today the RFC Editor is a small group funded by the Internet Society