Book excerpt: In a rapidly progressing field, Botulinum Toxin Therapy provides both clinicians and basic researchers with the latest science on the structure and function of botulinum toxins and the use of these toxins to treat a wide variety of diseases. Part 1 of the book reviews the basic science of botulinum toxins including advances in our understanding of the molecular structure and mechanism of action of botulinum toxins. This section also discusses the manufacturing and formulation of botulinum toxins for clinical use and the development of novel therapeutic toxins for the future. Part 2 reviews the use of botulinum toxins in clinical practice. It discusses the clinical pharmacology of botulinum toxin drugs and their use in a wide variety of clinical conditions including headache, spasticity, pain, disorders of the genitourinary and gastrointestinal tract, strabismus, and medical aesthetics.