This document discusses making apps Lightning Ready and provides guidance on the Lightning Ready process. It states that to be Lightning Ready, 100% of an app's end-user use cases must work as expected in Lightning Experience. It notes requirements for existing and new apps and answers common questions. The document also covers two guiding principles of Lightning Readiness - that a new customer on Lightning Experience can install and use the app successfully, and an existing customer can adopt Lightning Experience and continue using the app successfully.