The revised second edition addresses the complete range of conditions produced by this common disorder also known as APS or 'sticky blood' syndrome. APS is one of the main causes of strokes (40%), leg deep vein thrombosis, and recurrent miscarriages in women. It is an important risk factor for thrombosis in women taking the oral contraceptive pill. The effects of this syndrome were found initially in thrombosis, obstetrics (APS is the commonest treatable cause of recurrent pregnancy loss) and neurology. Its impact is now felt in a diverse range of conditions, including surgery (graft rejection), orthopedics (avascular necrosis, DVT), psychiatry (memory loss), cardiology (pulmonary hypertension, valvular disease, angina), ENT (vertigo), and pediatrics (young strokes, epilepsy). Described as one of the major new diseases of the late 20th century, APS is a multi-specialty disease and is of increasing interest to obstetricians, rheumatologists, hematologists, dermatologists, neurologists and immunologists.