This aims to provide an integrated "problem solving" approach. It encourages students to learn essential biochemistry by showing how biochemical "clues" lead to diagnosis and treatment of medical problems. It uses original data from clinicians and top scientists and sets out 22 problems cases, encompassing the key topics in undergraduate biochemistry including molecular biology and genetics. Each problem consists of a brief introduction; a medical case history; a number of specific questions, structured to provide a stepwise guide towards a solution; answers and discussion; further questions relating to the problem and up-to-date references. It aims to develop critical reasoning and data analysis skills, now seen as key skills in undergraduate teaching.