If you don't know that the incandescent light was a failure before it was a success, it's easy to write off some modern energy innovations like solar panels because they haven't hit the big time fast enough. Worse, the fairy-tale view of history implies that innovation has an end. But what we want and what we need keeps changing. The incandescent light was a 19th-century failure and a 20th-century success. Now it's a failure again, edged out by new technologies, like LEDs, that were also failures for many years. This issue is about all the little failures, trivialities and not-quite-solved mysteries that make the successes possible. This is what innovation looks like. Note: Click on the label headings to access each section. (Published June 1, 2012)