Mr. Sheffield is one of the premier writers of "hard" SF. The novel begins with one suspension of scientific principles: alpha centari goes supernova. This cannot happen happen by today's known mechanisms of supernova formation, as binaries that go supernova involve a dwarf star. Once this happens, however, Mr. Sheffield follows the consequences of a gamma ray blast from the exploded star that happens to emit in a direction that puts earth in the path. The EMP pulse devastates the computerized world by frying nearly every microchip on the planet. When this is added to the global weather changes, the problem is monumental. The novel focuses on events involving three main groups of people, one of which is the president of the United States.
Overall the novel flows pretty well, and the plot lines are interesting. The novel may have been better served by having one less major line to follow. This is particularly true of the events surrounding the US president. Many of the things that happen (such as a quiet dinner with one of his aides one evening) are hard to imagine in the face of the greatest disaster to strike Earth during recorded history. It is surreal to have the president having a quiet dinner and talking about an old flame when Australia and the whole of southern Africa are apparently gone due to the violent weather patterns in the southern hemisphere. The scene is reminescent of Nero playing the lyre while Rome burned, though this is not the author's intent. Overall, the novel is in the "good" range. More focus and stronger plot development could have made it "excellent."