This paper reviews advances in our knowledge of mechanoreception and nociception. Conventional microneurography has been used in combination with a new method of intraneural microstimulation to classify and activate single myelinated or small groups of unmyelinated sensory units in intact peripheral nerves in alert subjects. The results indicate exquisite capacity of the human brain to detect, localise, delineate, classify and quantify specific sensations from the input of certain types of single sensory units, particularly in fingertips. Application of the powerful technique of microstimulation has improved our understanding of the mechanisms underlying clinical tests such as two-point discrimination and point localization, and has shed new light on peripheral and central modulation of pain.