A Flexible System of Enzymatic Analysis is a multipurpose manual of laboratory methods that offers a systematic scheme for the analysis of biological materials from the level of the wholeorgan down to the single cell and beyond. It intends to guide the development of methods, the refinement of old ones, and the adaptation in general of methods to almost any scale of sensitivity. This manual is organized into three parts: a general section, one on quantitative histochemistry, and an appendix containing information that may be useful to have at the bench. The general section is comprised of nine chapters that focus on properties of the pyridine nucleotides, kinetics, and glassware, as well as on improvement, modification, adaptation, trouble shooting, and development of methods. This part also describes the preparation of tissues for analysis, the enzymatic cycling methods, and a compendium of 36 metabolite assays. The quantitative histochemistry section is comprised of four chapters that include information on the preparation of frozen-dried material and dissection of samples for analysis; the fishpole balance for weighing samples; and the generalities of analysis with emphasis on the "e;"e;oil well technique."e;"e; This book will be useful to novices as well as experts who are familiar with other analytical styles.