The Society is much saddened to hear of the death of Ricardo Miledi at the age of 90. Educated in Mexico and a skilled experimenter, he and Bernard Katz laid the foundations of our understanding of the role of calcium in synaptic neurotransmitter release. As well as making many basic discoveries on the acetylcholine receptor channel (including the first description of ‘acetylcholine noise’ with Katz), he was one of the early developers of the use of oocytes for drug-receptor expression studies. Succeeding Katz as head of the Department of Biophysics at UCL, he moved to the University of California Irvine in 1986. Amongst other awards, Ricardo Miledi held the Royal Society’s Fullerton Chair whilst at UCL and received its Royal Medal in 1998.