"From hydras to humans, this short book by two marine biologists explores the peculiar process of regeneration. . . . So here is the problem: if the mechanisms of regeneration can’t be distinguished from those of growth and development, what is to stop everything ceaselessly regenerating? What dictates the process of regrowth and why does it happen only in some tissues, in some species and only some of the time? Maienschein and MacCord argue that, to fully understand this, we need to see regeneration as a window into the world of biology in general, and the complex feedback loops that decide what grows, divides and dies, where and when. Far from being an interesting curio, then, studying regeneration can tell us much about life in general, from a cellular level right up to the level of ecosystems, and inform everything from regenerative therapies using stem cells to ecosystem protection and recovery. Seen through this lens, regeneration is a far bigger subject than it might at first seem."