Several important lessons emerge from these papers, and from the overall efforts of the semiconductor lithography community towards extending optical lithography beyond the 14-nm node. First and foremost, it can be done. The challenges are legion, but they are being met. Second, almost every detail is important (and bordering on the critical). Many effects once considered second or third order are now important enough to command considerable attention. But finally, an important question still remains: is it worth it? While we can extend optical lithography beyond the 14-nm node, should we? Will our companies remain profitable while trying to do so? This last question still awaits an answer. In the meantime, lithographers continue to do what they do best: push on.