This document provides an introduction to A/B testing for marketing optimization. It discusses how A/B testing, also known as split testing, can be used to compare different marketing variables and identify which performs better. The document recommends 10 guidelines for effective A/B testing, such as testing one variable at a time, measuring results as far down the funnel as possible, and setting up a control and treatment for accurate testing. It also explores what types of variables should be tested and provides examples of A/B testing case studies and best practices for running and evaluating tests. The overall document serves as a starting point for marketers looking to utilize A/B testing to improve marketing campaigns and optimize web pages, emails, and calls-to