Many formulations of the scientific method begin with observations. And the images here are indeed exciting observations — new pictures from Earth and space that will serve as the starting points for great science. But often the most arresting scientific images are captured at the end of the process, in the form of a solution. Such pictures represent the culmination of months of tireless work in the laboratory and have a still, completed quality. The structure of a protein or material, the high-resolution image revealing microscopic handiwork, the elegant visualization of data. Whether from the start or the end of an investigation — or from somewhere in between — these images are some of the most striking from 2007.