Throughout the ages, comets, those extraordinary, wandering celestial objects that, without warning, shine in the heavens for weeks or months, have impressed mankind. The ancient Greeks called them κομήτης, which meant ‘with long hair’ or ‘hair stars’. In other languages they were known as ‘broom stars’ (in English), or ‘tailed stars’ (‘staartster’ in Dutch). The German word ‘Schweifstern’ (‘stars with tails’) summarizes their diverse appearance.

The debate about these celestial bodies has been beset with errors and confusion, great ideas and amusing anecdotes. Beliefs and superstitions, art and science have all been influenced by the appearance of great comets. They reflect humanity's development and its search for explanations for appearances in the heavens.

The history of this development is described in this book though the descriptions of the 30 greatest comets from early modern times to the twenty-first century. In choosing these events, astronomical points of view were not the only criteria. The aim was to describe the strange ideas that had the greatest influence on people in former centuries.

This book would not have been possible without the help of numerous individuals. In particular, three people have had a great influence: great thanks are due to Hans Gaab, an expert on the astronomical history of Nuremberg, who placed extensive materials, books and copies at my disposal. His help was particularly valuable in the chapters on antiquity, the Middle Ages and early modern times.

Maik Meyer, who holds the record for the most comets discovered with the SOHO solar probe, and co-author with Gary W. Kronk of the multi-volume Cometography series of books, the world's most comprehensive documentation on comets, provided extremely significant help on discovery data and discovery statistics. Burkhard Leitner, the expert on comets on the editorial board of interstellarum magazine, provided the charts of the individual comet apparitions.

This illustrated work would not have appeared in such an opulent edition without the wonderful support from numerous astrophotographers.