Skin anatomy & physiology. Introduction ; The functions of the skin ; Skin components and structure ; Layers of the skin ; Summary -- Skin types, conditions & problems. Introduction ; The five basic questions ; Skin types ; Skin conditions ; Adverse reactions ; Summary -- How products work. Introduction ; Cosmetic ingredients ; Product and ingredient penetration ; Safety testing ; Efficacy testing ; Claim substantiation ; Summary -- Definition of terms. Introduction ; Commonly used terms defined -- Product ingredients -- Botanical Latin names. A dictionary of cosmetic ingredients and a guide to understanding skin types and skin physiology, product formulation and how cosmetic products interact with the skin.