This book is about an audacious idea: asteroengineering—literally, the physical engineering of a star, especially the star we call our Sun. It is an idea on the grandest of scales. Part science fiction, part science fact, asteroengineering is a response to a very definite and a very real problem, a problem that our distant descendants will one day have to face. It is also a universal problem that will be experienced – at some stage or other – by every extraterr- trial civilization that has or will exist. Indeed, the problem to be addressed resides within the parent stars of each and every li- supporting planetary system within our galaxy. In short, stars puff up to become luminous red giants as they age, and by doing this they vaporize those planets previously situated in the habitability zone where life can otherwise thrive. As their parent star ages and approaches the red giant phase, a civilization has two options open to it: stay at home, or pack up and leave. The latter option would require the hapless civilization to cocoon itself within giant spa- ships and then set itself adrift in the uncharted depths of space. If a civilization chooses to stay put, however, then all life will end—unless, that is, something is done about the demise of its parent star.