The primary aim of this book, Hedgehog Signaling Protocols, is to help Hedgehog researchers optimize their own practices, broaden their scope by adopting new methods and improve their understanding of more distant branches of the Hedgehog literature. The universally high quality of each chapter,authored by expert practitioners, guarantees some success in these objectives. Developmental biologists and educators with no special disposition towards Hedgehog signaling might also draw some benefit from this book as it provides a series of case studies that illustrate widely applicable methods. Some pragmatic details of the content of this book and some of its suggested uses are discussed below in order to help researchers and educators make a more precise personal evaluation of it.FIG1 

Half of the sixteen chapters, each of roughly a dozen pages, are devoted to a fairly comprehensive coverage of current techniques and key reagents used in Drosophila Hedgehog research. Particularly noteworthy is the conscientious compilation of GAL4 driver and UAS responder lines (Denise Busson and Anne-Marie Pret), which could save experienced researchers from having to comb through the literature and could also provide novices with instant familiarity with an important tool-kit. Also of note are the clearly explained benefits of a well-designed inducible RNAi vector (Eric Marois and Suzanne Eaton), which might not otherwise come to the attention of potential users. Two chapters on the use of Drosophila tissue culture cells for subcellular fractionation and the analysis of protein-protein interactions are written by experts (Melanie Stegman and David Robbins; Chao Tong and Jin Jiang) who have consistently achieved a standard in these areas that others try to emulate. Two other chapters focus on the detection of Hedgehog ligands and responses, highlighting honed immunocytochemical methods and reagents that are the fruits of the authors' extensive experience and success. The remaining four chapters focus on genetic methods for perturbing the Hedgehog pathway in Drosophila embryos and imaginal discs.

Although specific reagents and examples of results are included in all chapters, the underlying principles, which are generally carefully explained,together with generally applicable, detailed protocols, occupy at least two-thirds of the text. One associated benefit of that balance is that researchers new to the field (new PhD students, post-docs or bold PIs) will gain a good understanding of the principles and general rationale that underlie the detailed recipes for the execution of experiments in this field. A second benefit is that these chapters are also very useful to those outside the field of Hedgehog signaling because they offer a group of methods that are generally applicable to fly developmental biology. This volume might therefore be valued by many Drosophila research laboratories, especially those interested in intercellular signaling. There are, of course, several extensive reviews, websites, older books and even a very recent book from Humana Press on Drosophila research methodology, and several of those sources are indeed more comprehensive in breadth and detail than the fly chapters included here. Remarkably, however, much of the material is complementary rather than overlapping.

Those seeking guidance on how to study Hedgehog signaling in vertebrates will find single chapters centered on chick, Xenopus and zebrafish,which do a particularly nice job of providing a brief historical perspective and a balanced evaluation of the virtues and limitations of the approaches discussed. These chapters are supplemented by a very detailed and illuminating discussion of methods for purifying Hedgehog proteins in a variety of states of modification, which will be of universal interest within this field. They also include some practical advice on retroviruses and flow cytometry and a rather specialized discussion of working with rat telencephalic explants. Perhaps surprisingly, there are no chapters on some major areas of investigation, including Hedgehog signaling in the neural tube, cilia as key sites of Hedgehog signaling, genetic strategies in mice (akin to the Drosophila chapters) and on the analysis of Hedgehog pathway target genes.

What the book adds to research papers, descriptions in textbooks and reviews is a texture of reality borne of first-hand experience

As with any book, limitations stem from constraints on space and from being slightly out of date even at the time of publication. The 250 or so pages of this book are mostly concise and clear, as exemplified by the editor's four-page overview of Hedgehog signaling, and deal with topics and methods that should have enduring value and applicability for at least five or six years. Wisely, the book largely presents methods and concepts rather than attempting to convey a detailed current understanding of Hedgehog signaling,which would quickly become outdated and would always be surpassed by more current papers and reviews.

Investigators who are already running a Hedgehog research enterprise will probably find it difficult to decide whether this book is cost-efficient as a research training or experimental aid. It would certainly be a useful book to hand to new researchers in the laboratory. As mentioned, most chapters concern widely applicable techniques and, as such, this book would be helpful to many developmental biologists in training, especially in fly research, simply because of the balance of the book. What the book adds to research papers and most descriptions of methods in textbooks or review papers is a texture of reality, borne of first-hand experience. This is manifest in many chapters by the technical hints and very specific recommendations that are provided and in others by the organization and emphasis on the rationale for choosing a particular method that is often difficult to find in other publications. For those who remember the early days of molecular biology, there will never be a protocol manual to rival the impact of the original `Maniatis' volumes. Indeed, Hedgehog Signaling Protocols cannot be considered essential by that gold standard because it is not comprehensive or unique in its content, nor is it packed with secret tricks and treasures. However, the same memories might provoke the thought that a modest collection of methods books,spanning relevant disciplines and approaches, can be a very valuable resource in helping new arrivals to obtain a secure footing in a new field and to gain independence more quickly in a research laboratory.

Although this book is not written as a textbook, I can also imagine using it as a teaching device in graduate-level courses because it highlights certain methods accompanied by illustrative examples. This is a useful complement to research papers, which have the opposite emphasis, and to the discussion of methods in isolation, which can lack color and the important integration of means and objectives. This integration, coupled to suitably sophisticated and intellectually engaging genetics for a graduate course, are particularly noteworthy in the chapters on detecting the Hedgehog morphogen(Ainhoa Callejo, Luis Quijada and Isabel Guerrero), somatic clonal analysis(Christine Bankers and Joan Hooper) and on building a versatile RNAi vector(Eric Marois and Suzanne Eaton), all subjects that would find a place in many genetics and developmental biology courses. Of course, it might be a stretch to purchase a whole book in order to use only a few sections of it to augment a course based on additional materials. Unfortunately, analogous dilemmas of cost versus efficacy and fitting a text precisely to the complex demands of teaching or research are widespread. With Hedgehog Signaling Protocols you might not get exactly what you want, but if you try it out,as first vocalized more than a decade before the hedgehog gene was named, you might just get what you need!