Leading drosophilists describe in step-by-step detail all the essential techniques for studying Drosophila chromosomes and suggest new avenues for scientific exploration. The chapters emphasize specimen preparation (from dissection to mounting) and cover both polytene and mitotic/meiotic chromosomes in depth. Each fully tested and readily reproducible protocol offers a background introduction, equipment and reagent lists, and tips on troubleshooting and avoiding pitfalls. A cutting-edge FISH and immunolocalization technique will be important for discovering how DNA sequence influences higher-order chromosome architecture and ultimately gene expression.