This detailed book explores the technical breakthroughs with biophysical and cell biological approaches that have advanced the study of molecular mechanisms underlying the generation and transduction of the hedgehog (HH) signal, indicating the important role of sterols in this pathway. Within its pages, the volume examines techniques involving several key protein components in this pathway, including HH, the signaling ligand; Dispatched, a HH secretion regulator; Patched, the receptor of HH; Smoothened, the signal transducer used to transduce the HH signal across the plasma membrane; and GLI, the transcription factor to turn on HH target genes. Written in the highly successful Methods in Molecular Biology series format, chapters feature introductions to their respective topics, lists of the necessary materials and reagents, step-by-step readily reproducible laboratory protocols, as well as tips on troubleshooting and avoiding known pitfalls.