A Deterministic Turing Machine (DTM) is a theoretical model of computation that consists of an infinite tape, a tape head, and a set of rules. The tape serves as both input and memory, while the tape head reads and writes symbols on the tape. The machine operates in a step-by-step manner, following a specific set of instructions based on the current state and the symbol it reads. In a DTM, for every state and symbol combination, there is exactly one action to take, which includes writing a symbol, moving the tape head left or right, and transitioning to a new state. This predictability makes DTMs a fundamental concept in computer science and helps in understanding the limits of what can be computed.