Voller's second book on the subject puts Hubble and Humason on the same cover as partners in the discovery of the Big Bang experimentally. After a brief history of developments that set the table for this dynamic duo, he weaves the tale of each man's unlikely road to the field of astronomy and subsequent hiring at the Mount Wilson Observatory during the early 1920s. It is there where each makes his mark on the annals of science, first independently and in different departments, and finally together in pursuit of the answer to one of the great riddles in modern physics: is the universe expanding? Throughout the narrative, Voller unpacks the theory, the thoughts and the emotions of those involved in the race to understand the nature of cosmic dynamics in this revealing discourse on popular science. With Foreword by Carnegie Science President, John Mulchaey.