It is standard to say 'Darwin had nothing to say about microbes'. However, as discussed by Maureen O’Malley on pages 341–347, Darwin included microbes in his Beagle studies of the geographical distribution of organisms and used them as examples of how adaptation did not imply increasing complexity. However, his impact on microbiological thinking of the late nineteenth century was negligible. This limited impact is probably the key reason for the disassociation of Darwin and microbes that has persisted into contemporary biology and history of biology. Cover design by Philip Patenall.