Eclipse is a market-leading comprehensive treatment planning system that simplifies radiation therapy planning for all kinds of treatment, including 3-D conformal, IMRT, VMAT, electron, proton, and brachytherapy. It incorporates many tools that substantially speed up the process of planning complex radiotherapy treatments, including planning protocols and easy-to-use optimization tools. A new RapidPlan® knowledge-based planning tool provides planners with models that facilitate the rapid generation of high-quality plans.