If experience is any guide, it is safe to say that the next decade will be as full of surprises as the past decade. There is no doubt we will be surprised, so our job is to be prepared for the unexpected so that when it arrives, we have the fewest regrets. The Joint Operating Environment (JOE) is U.S. Joint Forces Command's review of possible future trends that present significant security challenges and opportunities for the next quarter-century. From economic trends to climate change, from cyber attacks to failed states, the JOE outlines future disruptions and examines the implications for our national security in general and for the joint force in particular. These implications, plus current operations, inform the concepts that drive our Services' adaptations and the environments within which they will operate.