Botulinum toxin type A (BTX-A) is the cornerstone of modern aesthetic practice, transforming facial rejuvenation with precision and versatility. Acting by transiently blocking acetylcholine release, it induces controlled muscle relaxation and glandular suppression. This chapter highlights the evolution of BTX-A, from its origins to current advances in first- and second-generation formulations with differing immunogenic profiles. Core indications include dynamic facial lines, masseter and temporalis hypertrophy, platysma bands, hyperhidrosis, and parotid gland hypertrophy. Off-label innovations such as microdroplet intradermal injection (“Microbotox/Mesobotox”) are emphasized for skin refinement, lifting, and contouring with natural outcomes. Practical insights into dosing, dilution, and anatomy-driven injection techniques are provided, along with strategies to avoid complications and resistance. Blending evidence-based science with clinical pearls, this chapter delivers an authoritative guide for safe, effective, and artistry-driven BTX-A treatments.