[the text below needs editing and we must be careful not to say things about Dan Brown's book that could get Springer in legal trouble]

Dan Brown's novel, The Da Vinci Code, was first published in 2003; its sales have reached 40 million worldwide. The book mixes a small spice of fact into a large dollop of fiction to create an entertaining novel of intrigue, adventure, romance, danger and conspiracy, which have been imaginatively worked together to cook up the successful bestseller.

Most interest in the book's origins has centred on the sensational religious aspects. Dan Brown has written: 'All of the art, architecture, secret rituals, secret societies, all of that is historical fact.' This gives an air of authenticity to the book. Brown has, however, made up the religious doctrines, or based them on questionable accounts by others.

The locations of the actions of The Da Vinci Code are not, however, made up. The present book is the scientific story behind the scene of several of the book's actions that take place on the axis of France that passes through Paris.

The Paris Meridian is the name of this location. It is the line running north-south through the astronomical observatory in Paris. One of the original intentions behind the founding of the Paris Observatory was to determine and measure this line. The French government financed the Paris Academy of Sciences to do so in the seventeenth to nineteenth centuries. It employed both astronomers - people who study and measure the stars - and geodesists - people who study and measure the Earth. This book is about what they did and why. It is a true story behind Dan Brown's fiction.

This is the first English language presentation of this historical material. It is attractively written and it features the story of the community of scientists who created the Paris Meridian. They knew each other well - some were members of the same families, in one caseof four generations. Like scientists everywhere they collaborated and formed alliances; they also split into warring factions and squabbled. They travelled to foreign countries, somehow transcending the national and political disputes, as scientists do now, their eyes fixed on ideas of accuracy, truth and objective, enduring values - save where the reception given to their own work is concerned, when some became blind to high ideals and descended into petty politics.

To establish the Paris Meridian, the scientists endured hardship, survived danger and gloried in amazing adventures during a time of turmoil in Europe, the French Revolution and the Napoleonic War between France and Spain. Some were accused of witchcraft. Some of their associates lost their heads on the guillotine. Some died of disease. Some won honour and fame. One became the Head of State in France, albeit for no more than a few weeks. Some found dangerous love in foreign countries. One scientist killed in self defence when attacked by a jealous lover, another was himself killed by a jealous lover, a third brought back a woman to France and then jilted her, whereupon she joined a convent.

The scientists worked on practical problems of interest to the government and to the people. They also worked on one of the important intellectual problems of the time, a problem of great interest to their fellow scientists all over the world, nothing less than the theory of universal gravitation. They succeeded in their intellectual work, while touching politics and the affairs of state. Their endeavours have left their marks on the landscape, in art and in literature.

From the reviews:

"This book was clearly a labor of love; Murdin has brought his passion for astronomy and its history to a topic which on the surface appears quite apart from this activity. ? The publisher has supported Murdin's effort with a physically appealing, aesthetic work, on high quality paper, complete with lovely diagrams and photographs. ? I recommend it for the general reader. ? For the motivated reader, the effort will be well rewarded with a picaresque journey through a relatively unknown section of scientific history." (Library Thing, May, 2009)

"The immediate impression of the book is quality ? . Murdin starts the journey with a very brief introduction to the relationship between mapping latitude and longitude and the movement of astronomical bodies such as Jupiter. ? Throughout the entire book, Murdin skillfully balances the technical details mapping techniques and instruments ? . Overall, this book is a handsome, quality, very readable volume that deserves a prominent position in any history of science and engineering." (Library Thing, April, 2009)

"British astronomer Murdin ? carefully examines the history of the Paris meridian in a work designed to highlight the adventures connected with the performance of what many might see as rather tedious research. ? In a report that stretches over centuries, Murdin is careful to define terms, introduce the important characters, and include many nice illustrations. ? Summing Up: Recommended. General readers." (M.-K. Hemenway, Choice, Vol. 46 (10), June, 2009)

"This modestly priced volume takes us on three journeys. The first is across the globe ? to discover the true figure of the Earth, and all this amid the turmoil surrounding the French Revolution. ? The second journey is through time, in which the role of the meridian is discussed ? . And finally, we are taken on a journey across Paris, along the meridian ? provided that the book can actas a guide for those wishing to follow the trail for themselves." (David Stickland, The Observatory, Vol. 129 (1213), December, 2009)