This issue of The Journal of Physiology includes a series of reviews that follow from the symposium 'Mitochondria in cell life and cell death' held at the FASEB Experimental Biology 2000 meeting in San Diego in April, 2000. The symposium is itself a clear testament to a resurgence of interest and excitement in mitochondrial biology. It feels as though the fundamental importance of mitochondrial biology in a wide range of biological questions has at last penetrated the collective scientific consciousness after years of neglect. The speakers were drawn from a range of biological areas, a reflection of the remarkably diverse roles of mitochondria in cell physiology and pathophysiology. Their contributions seem to fall into three main gro