This book reviews the role of each cell subset in the skin, providing the basics for understanding skin immunology and the mechanisms of skin diseases. The skin is one of the immune organs and is continually exposed to foreign antigens and external stimuli that must be monitored and characterized for possible elimination. Upon exposure to foreign antigens, the skin can elicit a variety of immune responses in harmony with skin components that include keratinocytes, dendritic cell subsets, mast cells, basophils, fibroblasts, macrophages, gamma-delta T cells, neutrophils, myeloid-derived...