The Transit of Venus is a rare event. It will next be witnessed in the USA during 2012. The story of how it was first observed is a missing chapter in the history of astronomy. Most people might name Newton or Edmund Halley as the greatest British astronomer, but both men drew heavily on the work of a mid-seventeenth-century man from Lancashire, Jeremiah Horrocks. Horrocks was a man ahead of his time. In 1639 he was the first person to see the image of Venus on the face of the sun. He appreciated the true scale of the solar system, charted the positions of the planets more accurately than ever before, and formulated a valid theory for the wanderings of the moon. In the period before the English Civil War of 1642-49, he was considered the greatest astronomer in the kingdom. He died at a tragically early age, but his legacy to science is quite remarkable. This book tells the story of how Horrocks came to predict and view the Transit of Venus in 1639 and emphasises the importance of his scientific legacy.