Many have learned from Professor Jeremy Morris, either directly or from his publications. Many others across the world have sometimes unknowingly followed his path. In July this year all had cause to celebrate his 90th birthday and honour him as an inspiration and founder of a broad gauged modern epidemiology. In this issue of the journal,1 writing with colleagues, he demonstrates his characteristic lifelong ingenuity and directness in the study of important public health problems. Not least among these is the search for keys to health across all sections of society. For many years and over the past 20 years especially, he has sharpened our insight into the iniquities of inequity. This new paper looks to answer a practical question posed by the emergent understanding of inequalities. More of this below.

Meanwhile, I turn to the context that gives the new paper broader meaning. Among the many accompaniments of social inequality, we can say with confidence that material differences and resources are an important element in creating health disparities. The Black Report of 1980, coauthored by Jerry Morris with Douglas Black, Cyril Smith, and Peter Townsend,2 stimulated much research devoted to demonstrating and explaining such disparities. This was so especially but not only in Britain, with little of the work welcomed by authorities faced with the ensuing political problem.

The link between poverty and disease has long been known. Johann Peter Frank in late 18th century Germany called poverty “the mother of disease”. Quantitative epidemiological study begins some decades later with Villermé. In 1826, he demonstrated across Parisian districts a gradient in mortality in close accord with the percentage of rents too low to tax; in 1840, in a six year study of the textile town of Mulhouse, he found striking gradients by occupation.3

What is remarkable …