David H. Hubel wrote:This book is mainly about the development of our ideas on how the brain handles visual information; it covers roughly the period between 1950 and 1980. The book is unabashedly concerned largely with research that I have been involved in or have taken a close interest in. I count myself lucky to have been around in that era, a time of excitement and fun. Some of the experiments have been arduous, or so it has often seemed at 4:00 A.M., especially when everything has gone wrong. But 98 percent of the time the work is exhilarating. There is a special immediacy to neurophysiological experiments: we can see and hear a cell respond to the stimuli we use and often realize, right at the time, what the responses imply for brain function. And in modern science, neurobiology is still an area in which one can work alone or with one colleague, on a budget that is minuscule by the standards of particle physics or astronomy. To have trained and worked on the North American continent has been a special piece of good luck, given the combination of a wonderful university system and a government that has consistently backed research in biology, especially in vision. I can only hope that we have the sense to cherish and preserve such blessings.

In writing the book I have had the astronomer in mind as my prototypical reader—someone with scientific training but not an expert in biology, let alone neurobiology. I have tried to give just enough background to make the neurobiology comprehensible, without loading the text down with material of interest only to experts. To steer a course between excessive superficiality and excessive detail has not been easy, especially because the very nature of the brain compels us to look at a wealth of articulated, interrelated details in order to come away with some sense of what it is and does.