Asthma is one of the most important diseases affecting our society. It is an extremely common condition that reduces quality of life, and acute exacerbations can be life--threatening. It affects a disproportionate number of children. With the overwhelming volume of research being carried out in this field specialists need a method of keeping up--to--date with current opinion. As with the other a Challengesa books, a Challenges in Asthmaa is aimed at hospital specialists and therefore assumes a certain level of knowledge about the disease. It builds on this by discussing only areas of controversy and uncertainty in both the basic understanding of asthma and its management. An international author list will provide stimulating debate with, and ultimately draw some conclusions from, existing data which will benefit readers in their day--to--day practice.