In proposing the existence of 'independent ego energies', the author attempts to revise the concept of 'desexualized libido' proposed by Freud and the theories of detached 'neutralized' energies, 'instincts of mastery', etc. posited in a variety of contexts by Hartmann, alone and together with Kris and Loewenstein, Anna Freud, Hendricks, Fenichel, Erikson and others. He suggests that only with the added postulate of an 'independent ego energy' which has no genetic or economic connexion with the libidinal or aggressive drives of the id, can a general theory of personality and psychological functioning be derived from Freud's metapsychology. Citing a variety of clinical, normal, developmental and animal experimental phenomena, the author proposes that when all known drives are at rest, adults, infants, chimpanzees and rats alike examine new objects, explore, search, manipulate and learn with no other force motivating them than the consummation of the activities themselves. Neither hunger, thirst,