Fossils hold an innate fascination for many people: finding a fossil on the seashore or in a quarry and realising that you are the first to see this creature for, say, 100 million years can be quite a moving - for some a spiritual - experience. Fossils, however, have more than symbolic or iconic status, for they are material evidence bearing on the greater question of the evolution of life on earth. In the historic past, they were thought of as quite literally anything dug up (encompassing a whole range of oddities), but today the term fossil has a much more restricted meaning: it is the preserved evidence of an organism or of its activity. Fossils also used to be discovered serendipitously, whereas now fossils can be, and are most often, found by the systematic exploration of geological strata of known type and age from specific areas of the globe. It is true to say that the whole "art" of fossil collecting has become a largely scientific, refined pursuit. Also, the collection of fossils is no longer an end in itself - it is just the beginning of a long and intricate path of scientific investigation and exploration that has many obvious and logical similarities to the work of a forensic pathologist associated with a modern police force. In both cases a body has been discovered, and there is a desire to understand the circumstances that led to the death and preservation of the cadaver.

Some early palaeontologists (comparative anatomists as they were then called) seemed to have an almost magical ability to conjure up the appearance of prehistoric creatures from the scrappiest of fossil remains. Paramount among such people was Georges Cuvier (based in the National Museum, Paris) at the beginning of the 19th century. How apt, therefore, that Philippe Taquet (an intellectual lineal descendant of Cuvier, from that same institution in Paris) should offer us Dinosaur Impressions , which endeavours to explain what palaeontologists get up to today. He uses as his example the sort of work that he has been doing for the past 30 years and provides a narrative of the more interesting aspects of his career. He focuses on his expedition work, which has covered many fascinating places: Saharan Africa, Southeast Asia, Mongolia and, of course, Europe. This provides the reader with a real feel for what it is like to be fortunate enough to be in Taquet's position. The book is also a relatively accessible account of the scientific significance of his discoveries, and those of others, so that the gently probing question - why? - receives a satisfying answer, too.

A few criticisms. The book would have been greatly enhanced by the inclusion of more photographs and illustrations. There are not nearly enough for this sort of account, which contains, as a matter of course, much visual allusion. My other reservation is the translation from French, which is rather wooden because it is too literal. This is a pity because the author writes elegantly in his own language.

Peter Ward's Time Machines is rather similar thematically to Taquet's book in that it too focuses on the fieldwork done by a palaeontologist and the science that flows from the discoveries, but the style and degree of elaboration of topics is different. Ward concentrates primarily on one area, the richly fossiliferous localities on and adjacent to Vancouver Island, off the northwest coast of North America. Then he begins to weave a tale that explores how discoveries made here are investigated from first principles and how they can be interwoven with discoveries and interpretations that may be of global significance - the small writ large. For example how do we estimate the age of rocks in which a fossil lies buried? This leads into detailed, but accessible, accounts of dating techniques based on fossils, radioactive decay and measurement of the polar magnetic signals left in rocks. From the last topic, we are led into a fascinating and unexpected discussion about the mechanics of plate tectonics and the possible relationship between different parts (ie north and south) of the west coast of North America, and thus how time and place become very important in the history of life on earth.

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With regard to place, Ward examines the way in which the locations of fossil finds can lead us, through careful study, to the environments in which such former animals lived - using the animals and their sedimentary environment as clues (rather like a forensic pathologist). He goes on to explore how life-and-death scenarios (stories) have been created around certain, almost iconic fossils, such as ammonite shells showing rows of puncture holes, which have been nearly universally accepted as the "bite marks" from attacks by giant marine reptiles. Ward first attempts to sow seeds of doubt over this scenario and then, through a series of interesting (though not-so-convincing experiments) "proves", or at least expounds, an interesting alternative origin for these puncture marks.

Finally, Ward employs the technique of taking the reader on an imaginative voyage back in time, a scuba dive through the world inhabited by the marine animals he has just described.

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Both of these books provide good, practical insight into the work and strivings of palaeontologists. Both are interesting narratives (despite my misgivings about the translation of Taquet's book), and both bring not a little passion to a subject that is often the butt of jokes, such as the waggish: "Fossils, oh yes, don't move much do they? - ho, ho!". If you know one of these oafs, treat him to either of these books as a present. They are modestly priced, and you might even be thanked for it.

David Norman is director, Sedgwick Museum, University of Cambridge.