The book of Cliff and Ord The problem of spatial autocorrelation (1969) has become a classic in human geography. The special issue celebrates it as the beginning of the dissemination of their innovative thinking and of their major interdisciplinary
and multidisciplinary contribution to science and to theoretical geography. The commentaries included in the issue cover thematic and methodological areas in which spatial autocorrelation flourishes : criminology, ecology, epidemiology, geography, housing and house
prices, local statistics, network autocorrelation, spatial econometrics, spatial simulation, statistics, and the nature of the geographic weights matrix.