I arranged with the Warburg Institute to take my son to visit its library and archive. I had scarcely been back since I was a postgraduate student there in the late 1970s. Little has changed: the open access stacks of the library arranged according to Warburg’s intellectual principles, such that a Renaissance treatise is shelved next to the latest offprint; the gunmetal grey filing cabinets of the Photographic Collection where I worked every Friday. I had never seen the archive which was established in the early 1990s to make Warburg’s own papers more publicly available. They still have serried ranks of card index boxes in which Warburg developed the intellectual system of his ideas, neat little rows of notes interleaved with articles, images and transcripts from early twentieth century books and journals. What comes across is the continuing relevance of Warburg’s ideas and the intellectual integrity of the library as a whole, which makes it more baffling that London University should have challenged the terms of the Warburg family’s 1944 deed of trust in court.