Concluding remarks

I present a summary of some of my concluding remarks from the conference The Extreme and Variable High Energy Sky. The meeting represented both a celebration of the 9th anniversary of the launch of INTEGRAL, and a broad discussion of high energy astrophysics in general - resulting in a nice scientific program which also exposed the key results of INTEGRAL to a broader community. While at the original meeting, I presented a one or two sentence summary for every talk, and closed with a few unifying thoughts, this paper will focus on the unifying thoughts, since the proceedings will be available for the rest of the meeting's talks. One of these themes is that gamma-ray missions often achieve key results only late in their mission lifetimes, with a few of the exciting recent results from INTEGRAL shown at the meeting representing good examples of this. Another is a rapid change coming in the high energy landscape (with RXTE coming down, and NuStar soon due to launch), which may change the role INTEGRAL plays in the high energy astrophysicist's toolkit. A final point is a discussion of the need for a new approach to calibration at high energies in the era of much higher sensitivity observatories, including the recognition that where rarely used modes exist at all, they often have the potential to represent the most major breakthroughs from a mission, and deserve a share of the ground calibration effort far in excess of the share of the observatory time they are expected to use.