In general, there are three types of communication in walker-assisted gait applications. On the one hand, Human–Robot Interaction refers to the features and strategies of the device that allow it to communicate physically and cognitively with the user. Similarly, Robot–Environment Interaction refers to the device’s operation in a given environment. It also involves the sensors that acquire information from the environment. Finally, Human–Robot–Environment Interaction comprises the device, the user, the environment, and the clinicians in a communication channel that is natural, safe, and efficient. Thus, this chapter presents the necessary fundamentals to understand the control strategies that govern these interaction types. It also provides basic design notions to propose new control strategies for robotic walkers.