The term telogen effluvium, first coined by Kligman in 1961, refers to the loss of club (telogen) hair in disease states of the follicle. Kligman's hypothesis was that whatever the cause of hair loss, the follicle tends to behave in a similar way, namely the premature termination of anagen. "The follicle is precipitated into catagen and transforms into a resting stage that mimics telogen." Ipso facto the observation of telogen hair loss does not infer a cause. To establish the cause of the hair loss, one requires a history to identify known triggers, biochemical investigations to exclude endocrine, nutritional or autoimmune aetiologies and in many cases histology to identify the earliest stages of androgenetic alopecia. The duration of the hair loss at presentation helps predict those patients in whom further investigation will have the greatest yield. "It is unfortunate that baldness has been approached with an eye toward "regrowing" or "restoring hair", and thus with a tendency toward commercialism. Locked within the metamorphosing hair follicles in the balding scalp are all the secrets of growth and differentation. Searching for these secrets should transcend the eagerness to "regrow" hair on a bald scalp, an achievement which is of no great consequence. When we know these answers, we shall have the key, not to hair growth alone, but to all growth, which is, after all, the basis of all biological phenomena." William Montagna, 1959.