Psoriasis is a common, inflammatory, multisystemic skin disease characterised by hyperproliferation and abnormal differentiation of epidermis. There is a wide variety of therapeutic options to treat psoriasis including topical, phototherapy, systemic and biological therapies. During the past decade, many pathological models have been developed to better understand psoriasis. Among them, in-vitro models offer an interesting alternative to animal models. The development of these models represents a key component in the fight against psoriasis. This book presents the characteristics of this pathology, the suggested causes, the treatments and the current state of research on pathological models to better understand mechanisms of psoriasis.