1.1 Intended Readership

This document, the "SOFIA Observer's Handbook for Cycle 5" (hereafter the Observer's Handbook), provides information about SOFIA operations and the instruments that will be available for observations during Cycle 5, nominally scheduled for 1 February, 2017 - 31 January, 2018. The Observer's Handbook is the primary technical reference for astronomers who wish to submit a proposal for SOFIA Cycle 5. The information contained herein, and in documents and websites explicitly referred to, should be sufficient to allow proposers to plan viable SOFIA observations.