Our relationship with the physical world is rich, complex, and essential for life. Our research explores the properties and functions of somatosensory neurons and the functional organization of the subcortical somatosensory circuitry and the neural encoding of touch and pain. We have generated an array of mouse genetic tools for interrogating the physiologically distinct classes of Low-Threshold Mechanoreceptors (LTMRs), which are the primary sensory neurons of touch, as well as HTMRs and other somatosensory neuron subtypes. These genetic tools are the lab’s engine of discovery that enable advanced physiological, anatomical, molecular, and behavioral analyses of the mammalian somatosensory system. Our contributions have included: 1) Revealing morphological and molecular bases of LTMR subtype physiological response properties; 2) Uncovering organizational principles of spinal cord and brainstem touch circuitry and a new conceptual framework for understanding how LTMR activity ensembles are integrated within the earliest stages of the somatosensory hierarchy; 3) Defining properties and functions of spinal cord projection neurons that convey discriminative touch as well as affective touch and pain signals to the brain; 4) Identifying extrinsic cues and signaling pathways that shape PNS and spinal cord development; and 5) Revealing dysfunction of sensory neurons and spinal cord circuit motifs underlying aberrant touch reactivity in models of autism spectrum disorders and pain, and new therapeutic opportunities. Advanced genetic tools and methodologies are currently being used to explore the ultrastructural basis of LTMR response properties, unique functions of LTMR subtypes across the body, and the organizational logic of LTMR synapses in the spinal cord and brainstem that underlie tactile feature representation, pain, and autonomic reflexes.