Comets are always very impressive phenomena. Their appearances at regular, but mostly irregular, times excite people who see them. Astronomers have the obvious advantage of being able to see more of comets, and to study them. Their enthusiasm is reflected in the 50 papers in this book, written by more than 90 experts.
The reviews in this book clearly describe a landmark in the history of cometary studies. Knowledge gathered up to and including Comet Halley are presented in two volumes. The first volume is about general aspects of observing and studying comets, where they originate and how their evolution develops.
The second volume goes into the details of what a comet is: the nucleus, the coma, cometary dust, plasmas and magnetic fields. The book ends with a reflection by Fred Whipple about Comets in the Post-Halley Era.
The book discusses all aspects of comets and is therefore suitable for use in graduate level courses. All astronomers and geophysicists interested in comets will find very useful and well-presented information in this book.

Section I: Observing Techniques and Interpretation.- Cometary Orbital Dynamics and Astrometry.- Cometary Photometry.- Infrared Techniques for Comet Observations.- Infrared Spectroscopy of Cometary Parent Molecules.- Carbonaceous Compounds in Comets: Infrared Observations.- Ultraviolet Spectroscopy of Cometary Comae.- The Study of Comets at Radio Wavelengths.- A Review of Radio Interferometric Imaging of Comets.- The Modern Role of Visual Observations of Comets.- Section II: Laboratory Studies and Simulations.- Physical Properties of Frozen Volatiles-Their Relevance to the Study of Comet Nuclei.- Irradiation Effects on Comets and Cometary Debris.- Laboratory Simulation of Cometary Processes: Results From First KOSI Experiments.- Laboratory Simulation of Cometary Structures.- Recent Laboratory Photochemical Studies and Their Relationship to the Photochemical Formation of Cometary Radicals.- Section III: Comets, Origins, and Evolution.- The Accumulation and Structure of Comets.- Chemical Theories on the Origin of Comets.- Nature and History of the Organic Compounds in Comets: An Astrophysical View.- Noble Gases in Terrestrial Planets: Evidence for Cometary Impacts?.- Biological Implications of Organic Compounds in Comets.- Dynamical History of the Oort Cloud.- Statistical and Evolutionary Aspects of Cometary Orbits.- End Products of Cometary Evolution: Cometary Origin of Earth-Crossing Bodies of Asteroidal Appearance.- Debris From Comets: The Evolution of Meteor Streams.- Evolution of Cometary Debris: Physical Aspects.- Evidence for Physical Aging of Periodic Comets.- Physical Aging in Comets.- Contributing Authors.