This Thesis describes the use of synthetic chemistry to investigate mechanisms for controlling molecular-level motion. Initially, the principles that all experimental designs for working molecular machines must follow are elucidated; tracing the development of ideas about molecular-level motion from their genesis, to the modern-day contributions of molecular biology and theoretical nonequilibrium statistical physics. In the rest of the Thesis, these theoretical considerations are applied and extended through the construction and operation of molecular machines based on interlocked molecules. Two simple rotaxane-based examples serve to demonstrate the novel concept of ‘compartmentalized’ molecular machines. Correlating chemical, physical and statistical descriptions of these simple devices with their behaviour, reveals the fundamental mechanistic elements that are involved in the operation of any compartmentalized Brownian machine and suggests how these can be combined to create different types of device. This leads to the construction of a [2]catenane that is the first example of a reversible synthetic rotary molecular motor and which operates via an energy ratchet mechanism. Next, a fundamentally different mechanism is investigated through the construction and analysis of a compartmentalized molecular machine that is the first to operate via an information ratchet mechanism. Finally, the classic stimuli-responsive molecular shuttle design serves as an ideal test bed for investigating a new structural series of rotaxane-based molecular machines that are controlled by redox processes and which show promise for operation at surfaces.