This chapter establishes the first foundational principle in the design of integrated haptic systems: the link between the mechanical behavior of human skin and the perceptual experiences it gives rise to. Human touch is fundamentally a process of mechanical stimulation interpreted by the nervous system. Every tactile experience begins with the deformation of the skin under contact. Understanding how these mechanical events are encoded and transformed into perceptual responses provides the scientific grounding for designing integrated haptic systems that can replicate or interface with the natural human sense of touch.