Teaching the Essential Principles of Development Essential Developmental Biology. (2001). Jonathan Slack. Blackwell Science Ltd, Oxford. vi þ 321 pp. $50.00. ISBN 0- 632-05233-3. Principles of Development, 2nd edition. (2002). Lewis Wolpert, Rosa Beddington, Thomas Jessell, Peter Lawrence, Elliot Meyerowitz, Jim Smith. Oxford University Press, New York. xxv þ 542 pp. $89.95. ISBN 0-19-924939-3. Reviewed by Mary Pfann Savage Biology Department UW-Whitewater, 315 Upham Hall Whitewater, WI 53190. John F. Fallon Dept. of Anatomy University of Wisconsin-Madison 1300 University Ave., Madison WI 53706. Jeff Hardin Dept. of Zoology University of Wisconsin-Madison 1117 W. Johnson St., Madison WI 53706. A revolution in understanding developmental biology has been fueled by molecular and genetic approaches to the discipline. Two recently published textbooks of Developmental Biology are worthy contenders in the fight to maintain perspective in the midst of this molecular detail. Essentials of Developmental Biology by Jonathan Slack and Principles of Development by Lewis Wolpert, Rosa Beddington, Thomas Jessell, Peter Lawrence, Elliot Meyerowitz, and Jim Smith are intended as introductions and overviews of the field suitable for undergraduate students. While both texts present the major principles and support- ing evidence to the student, their approach to the material is very different. Slack focuses on the understanding of devel- opment gained through molecular and genetic experiments. In his streamlined presentation each sentence counts; theories and supporting experimental evidence are presented but interpretation is left largely to the student and instructor. This minimalist approach emphasizes the modern view over the classical. In contrast, Wolpert et al. present a more detailed narrative. Here too, the emphasis is on current molecular and genetic evidence, but such details are incorporated in the context of classical experiments. Wolpert et al. use the ex- perimental evidence to promote and support their conceptual framework as a unified theory of development. The decision of which text to choose is based in part on teaching style. Instructors often use either a top-down or a bottom-up approach. In the top-down approach, the instructor uses a detailed text and winnows the essential material for the student. In a bottom-up approach, the instructor uses a sparse text as a foundation, then supplements with lectures, additional readings from the literature, popular press or other texts. Wolpert et al. approaches development from the top- down: they present concepts, theories and interpretations; experiments are used as support. Slack moves from the bottom-up: he presents the data that the teacher and student use to further their own synthesis. Content The overall content of the texts is similar. Chapters can be grouped together: First are the Basics, as each text presents an overview of the field, its basic principles and techniques. Second are the Common Events of early embryology. Third are Selected Topics, including organogenesis or other later events. The Basics of Slack’s text immediately establishes the importance of current molecular approaches, with an entire chapter that identifies key molecular components, another chapter that covers developmental genetics, and a third that describes experimental techniques. The molecular chapter includes a very useful Appendix that describes some devel- opmentally important gene products and families. Chapters on Major Model Organisms cover Common Events. Here Slack addresses common features of development in one chapter, followed by details of the major model organisms used in many developmental biology laboratories. In each of these chapters, specific techniques and developmental processes that are particularly well suited to each system are amplified. Slack has an excellent section on mouse technology that includes basic information on embryonic stem cells, knockout and transgenic mice, selectable expression via the Cre-lox system and enhancer traps. Selected Topics include chapters on: the nervous system, mesodermal organs, imaginal discs, stem cells, and regeneration. Wolpert et al.’s text, though not formally subdivided, can be split into three units as well. The Basics begins with a more historical perspective that incorporates the descriptive embry- ology of some of the major model organisms. Conceptual tools and theories, including organization of complex structures through pattern formation, cellular behavior and differential gene activity follow. Unlike Slack, key molecular components are presented in the specific context within which they are discussed. The Common Events, according to Wolpert et al., are involved in patterning of the body plan. This theme unifies chapters about vertebrates, Drosophila, invertebrates and plants. Each of these chapters addresses, in depth, the em- bryology, experimental approach and molecular components of developmental processes, such as axis formation or speci- fication of germ layers. Only after setting up body plans do Wolpert et al. address processes of morphogenesis, cell differentiation and gene expression. Selected Topics include organogenesis, nervous system, germ cells, regeneration, growth, and evolution to complete this text. Compared with the very concise treatment offered by BioEssays 25:301–302, ß 2003 Wiley Periodicals, Inc. BioEssays 25.3 301 Book reviews