The stars are so distant that even at high power through a telescope they look like nothing more than colorful points of light. In "Extreme Stars", Kaler shows us that in fact these little luminaries of our night sky come in an astonishing variety of temperatures, sizes, absolute brightnesses, and chemical compositions. A chapter is devoted to each type of extreme star, e.g. the coolest, brightest, youngest, etc.To me, the most interesting theme of the book is how a single star can actually change from one extreme type to another over its lifetime. For example, the brightest stars (accounting for 'unseen' radiation like ultraviolet and infrared) are the blue supergiants. These inevitably go supernova and often leave behind neutron star cores, which are both the smallest and hottest of stars. Also, the coolest red giants will form planetary nebulae and leave behind white dwarfs, which comprise one of the hottest types of stars at the outset. Another example is the faintest stars, which are so frugal with their fuel consumption that they have the longest lifespans and therefore will be the oldest stars.The book is written with great enthusiasm and is well illustrated. I do remember one time that Kaler kind of took it into the deep end with his discussion of electron degeneracy and the Pauli Exclusion Principle, but for the most part the book is easily accessible to the interested layman. Amateur astronomers like myself would really dig it.After reading the book, it made me want to get the telescope out and simply stare at some of these extreme stars for a while. The easiest ones to learn to identify by naked eye are the bright supergiants, like Betelgeuse and Deneb. But there are plenty of others in the other extreme types that are bright enough to see with the naked eye; these can be located with a decent star atlas.One minor quibble: I feel that Kaler didn't emphasize enough that the vast majority of stars we see are just regular main sequence stars, ranging from perhaps 0.2 to three or four times the mass of the Sun. Extreme stars are relatively rare.Highly recommended.