Assembly language is a low-level programming language that closely corresponds to machine code, using mnemonics to represent CPU instructions. It provides direct control over hardware and memory, making it essential for tasks requiring granular analysis and manipulation. Assembly language is foundational for cybersecurity because it enables deep introspection and manipulation of software behavior. Mastery of assembly equips professionals to reverse engineer binaries, dissect malware, and develop exploits, bridging the gap between high-level abstractions and hardware-level execution.