Herewe offer anew approach to understanding and managing common medical conditions. With the needs of our readers in mind we present clearer, more extensive and more expansive views on them. Traditional medical textbooks are wordy tomes with well worn patterns dealing in set order with 'causes, symptoms and signs, diagnosis and treatment'. They offer formal instant snapshots of diseases. We have devised an economic synoptic style, and we have endeavoured to give acomprehensive and an on-going long term movepicture ofeach condition and to relate this to the analysisofsymptoms and signs, to diagnostic assessment and to management and treatment. We have selected 22 important conditions and for eachhave followed the same sequence of questions and answers: • What is it? giving a brief summary of the current understanding of the nature of the condition. • Who gets it when? showing the age-sex distributions and influence ofother factors such as social class, international comparisons, andtheirlikelyfrequency ingeneralpractice and at the district general hospital. • What happens? analysing the significance of symptoms and signs, the likely course and outcome and how these influence care. • What to do? an appreciation of the nature and presentation of the condition, and their relevance to diagnosis and management.