DNA Topoisomerase Protocols is an unprecedented collection of cutting-edge experimental protocols for investigating DNA structure, topology, and DNA topoisomerase function. Described by expert experimentalists who have perfected the techniques, these time-proven methods utilize new approaches to study changes in DNA topology (linking number, knotting, catenation, and relaxation) and DNA structure (bending), as well as to assess chromosome structure through FLP-mediated recombination and to analyze bacterial nucleoid structure. State-of-the-art protocols also detail the expression and purification of bacterial, viral, and eukaryotic DNA topoisomerases from a variety of sources, including baculovirus, bacterial, yeast, and mammalian expression systems.