This document provides an overview and introduction to affiliate marketing programs and Clickbank, a popular affiliate network. It defines what affiliate programs are and how they work at a high level, with affiliates earning commissions for generating sales or leads for a merchant. It then discusses some of the key aspects of affiliate programs, including different payment models, brokers/networks, and a brief history. Finally, it introduces Clickbank as a commonly used affiliate network and previews that more details on Clickbank will be covered starting on page 16.