"The Hope of Progress" is the title of a collection of essays [1] by Peter Medawar, who won the Nobel Prize in Physiology or Medicine in 1960, jointly with Frank McFarlane Burnet, for his research in immunology. The sentence from which the phrase is taken - "To deride the hope of progress is the ultimate fatuity, the last word in poverty of spirit and meanness of mind" - may strike us as overelaborate and flowery in this texting and blogging age when the analogous sentiment is expressed as "Yes we can". But Medawar was remarkable for his clarity of thought, as well as for his (now unfashionable) elegance of expression, and his research on transplant rejection led to the discovery of principles fundamental to modern immunology; so the phrase seems apt as a title for a new series that we are launching with three contributions on biology relevant to clinical problems. Two of the three contributions are reviews - by Christopher Lord and Alan Ashworth on the development of new cancer therapeutic drugs [2], and by Amy McKee, Megan McLeod, John Kappler and Philippa Marrack [3] on adjuvants and vaccine development. The third is a new feature, a video Q&A (see [4]), in which Martin Raff explains his interest in, and delivers his views on research on the biological basis of autism, both in video and in text format [5].