Historically, haptics—all different aspects of the sense of touch and its study—has developed around very technical and scientific inquiries. Despite considerable haptic research advances and the obviousness of haptics in everyday life, this modality remains mostly foreign and unfamiliar to designers. The guiding motif of this research relates to a desire to reverse the situation and have designers designing for and with the haptic sense, for human use and looking beyond technical advances. Consequently, this thesis aims to nurture the development of haptics from a designerly perspective, leading to a new field of activities labeled haptic interaction design. It advances that haptic attributes and characteristics are increasingly part of the qualities that make up the interactions and the experiences we have with objects and the interfaces that surround us, and that these considerations can and ought to be knowingly and explicitly designed by designers. The book encompasses an annotated research through design exploration of the developing field of haptic interaction design, building on a considerable account of self-initiated individual design activities and empirical-style group activities with others. This extensive investigation of designing haptic interactions leads to the Simple Haptics proposition, an approach to ease the discovery and appropriation of haptics by designers. Simple Haptics consists in a simplistic, rustic approach to the design of haptic interactions, and advocates an effervescence of direct perceptual experiences in lieu of technical reverence. Simple Haptics boils down to three main traits: 1) a reliance on sketching in hardware to engage with haptics; 2) a fondness for basic, uncomplicated, and accessible tools and materials for the design of haptic interactions; and 3) a strong focus on experiential and directly experiencable perceptual qualities of haptics.  Ultimately, this thesis offers contributions related to the design of haptic interactions. The main knowledge contribution relates to the massification of haptics, i.e. the intentional realization and appropriation of haptics—with its dimensions and qualities—as a non-visual interaction design material. Methodologically, this work suggests a mixed longitudinal approach to haptics in a form of a well-grounded interplay between personal inquiries and external perspectives. The book also presents design contributions as ways to practically, physically and tangibly access, realize and explore haptic interactions. Globally these contributions help make haptics concrete, graspable, sensible and approachable for designers. The hope is to inspire design researchers, students and practitioners to discover and value haptics as a core component of any interaction design activities.