This document provides guidance for traditional software companies transitioning to a Software as a Service (SaaS) model. It discusses the industry shift toward SaaS delivery and the challenges and opportunities companies will face. It outlines four transition archetypes - traditional, hybrid, cross-over, pure SaaS - and recommends a five step process for a successful transition: 1) start with the desired end state in mind, 2) think customers first, 3) build a lead generation machine, 4) sell a service not a product, and 5) drive customer success. The document provides advice on segmentation, costs, automation, metrics and building a customer community to support the transition.