Many advances have been made in our understanding of the biology of psoriasis over the past 20 years. We are close to knowing the genetic determinants of psoriasis. There is now greater insight into the immunological mechanisms that produce the phenotype, and the possibility of intervening selectively to antagonise some of these mechanisms is becoming a reality. Nevertheless, psoriasis remains an enigmatic disease, and much of the suffering it produces is not adequately addressed. The sheer number of treatments that are used therapeutically suggests a lack of efficacy and/or toxicity of many of these approaches. In this review, we aim to briefly describe the biology of psoriasis, document the key features of treatments that are available or under development, and explain how these treatments can be used effectively to manage this chronic relapsing disease.