Alopecia or baldness is a common problem that can cause worry and stress to patients. The evaluation of hair loss remains a difficult and confusing subject for most physicians. A careful history should cover the questions of shedding versus thinning and the duration and family history. Evidence of scarring or non-scarring on the scalp surface, pattern of hair loss, which can be diffuse or confined to one or several areas of the scalp should be noted. Special investigative techniques include the gentle hair pull, the forcible hair pluck with forceps, scalp biopsy and some laboratory tests. This article concludes that the historic and clinical clues of common baldness, such as telogen effluvium, androgenic alopecia, female pattern hair loss, alopecia areata, trichotillomania, and alopecia in systemic diseases are important for the diagnosis, management plan and prognosis of the disease.