By studying evolution across geological time, paleontologists gain a perspective that sometimes complements and sometimes conflicts with views based solely on studies of extant species. The contributors to Causes of Evolution consider whether factors exerting major influences on evolution are biotic or abiotic, intrinsic or extrinsic.

Causes of Evolution presents a broad sampling of paleontological research programs encompassing vertebrates, invertebrates, and vascular plants; empirical work and theoretical models; organisms ranging in age from Cambrian to Recent; and temporal scales from ecological time to hundreds of millions of years. The diverse array of research styles and opinions presented will acquaint scientists in related fields with the strengths and weaknesses of paleontology as an approach to evolutionary studies and will give evolutionary biologists of every stripe new bases for evaluating the scope and bias of their own work.

Two tiny trilobites in a vast Cambrian ocean drift past sea cucumber parasols and a shaggy, tree-like sponge. Snail tracks loop enigmatically against brushed-gray Silurian slate, and ghostly white crinoids feather a Devonian seascape. A delicate pterosaur flies bravely into the Jurassic gloom, while a Tyrannosaurus rex so big that its teeth fill our field of vision stalks the deep orange sands that mark the end of the Cretaceous period.

These are just a few scenes from the magnificent drama that unfolds in glorious full color and three-dimensional texture in Rock of Ages, Sands of Time. Each of Barbara Page's 544 contiguous painted panels represents a million years of the history of life on earth, with fossil plants and animals depicted at the same scale and in association with each other just as they might be found by a paleontologist in the field. A muted rainbow of background colors evoke the rocks in which the fossils were found—the Texas Red Beds, for instance, or the yellow Solnhofen limestone—and keystone events are shown metaphorically, with fat rolls of paint marking major extinctions or continental drift.

To fully experience the awesome impact of an eon's worth of time spread across 500 feet of bas-relief panels, you'd have to visit the Museum of the Earth in Ithaca, New York, where Page's specially commissioned work will be installed when the museum opens in 2002. But this book is the next best thing. Not only does it contain crisp color reproductions of each painting, but it also includes an accessible essay from paleontologist Warren Allmon giving the scientific context behind the art.

For fossil lovers of all ages, and anyone interested in the merging of art and science, Rock of Ages, Sands of Time will be the find of a lifetime.

Although the species is one of the fundamental units of biological classification, there is remarkably little consensus among biologists about what defines a species, even within distinct sub-disciplines. The literature of paleobiology, in particular, is littered with qualifiers and cautions about applying the term to the fossil record or equating such species with those recognized among living organisms. In Species and Speciation in the Fossil Record, experts in the field examine how they conceive of species of fossil animals and consider the implications these different approaches have for thinking about species in the context of macroevolution.

After outlining views of the Modern Synthesis of evolutionary disciplines and detailing the development within paleobiology of quantitative methods for documenting and analyzing variation within fossil assemblages, contributors explore the challenges of recognizing and defining species from fossil specimens—and offer potential solutions. Addressing both the tempo and mode of speciation over time, they show how with careful interpretation and a clear species concept, fossil species may be sufficiently robust for meaningful paleobiological analyses. Indeed, they demonstrate that the species concept, if more refined, could unearth a wealth of information about the interplay between species origins and extinctions, between local and global climate change, and greatly deepen our understanding of the evolution of life.