Book excerpt: David Levy has held a lifelong passion for comets, and is one of the most successful comet discoverers in history. In this book he describes the observing techniques that have been developed over the years--from visual observations and searching, to photography, through to electronic charge-coupled devices (CCDs). He combines the history of comet hunting with the latest techniques, showing how our understanding of comets has evolved over time. This practical handbook is suitable for amateur astronomers, from those who are casually interested in comets and how to observe them, to those who want to begin and expand an observing program of their own. Drawing widely from his own extensive experience, Levy describes how enthusiastic amateurs can observe comets and try to make new discoveries themselves. David H. Levy is one of the word's foremost amateur astronomers. He has discovered seventeen comets, seven using a telescope in his own backyard, and had a minor planet, Asteroid 3673 Levy named in his honor. He is best known as the co-discoverer of the famous 1994 Shoemaker-Levy 9 comet. Levy is frequently interviewed in the media and succeeded Carl Sagan as science columnist for Parade magazine. He has written and contributed to a number of books, most recently David Levy's Guide to the Night Sky (Cambridge, 2001).