IETF review of an Applicability Statement for the core email protocols exposed considerable confusion about the applicability and effectiveness of various techniques for authenticating email and keeping messages and their various elements confidential. Equally or more important, there is confusion about the relationships among various possible methods and tools, with the documents of those methods, taken one at a time, often failing to address those relationships and the tradeoffs involved explicitly. This document describes the various approaches with their strengths and weaknesses, and provides advice about best practices under different conditions.