Differential temperature changes with altitude can shed light on the relative importance of natural versus anthropogenic climatic change. There has been heightened interest in this subject recently due to the finding that high-elevation tropical glaciers have been retreating and that significant melting from even the highest alpine regions has occurred in some areas during the past 20 years or so, as recorded in ice core records, which do not reveal any similar period during previous centuries to millennia. In this paper we find evidence for appreciable differences in mean temperature changes with elevation during the last several decades of instrumental records. The signal appears to be more closely related to increases in daily minimum temperature than changes in the daily maximum. The changes in surface temperature vary spatially, with Europe (particularly western Europe), and parts of Asia displaying the strongest high altitude warming during the period of record. High-elevation climate records of long standing taken at a number of mountain tops throughout the world, but primarily in Europe, are available from a number of countries. In some cases, meteorological observations at these unique mountain sites have been discontinued for a variety of reasons, usually budgetary. It is hoped that the papers published in this special issue of Climatic Change can contribute to a reassessment of the value of continuing climate measurements at these mountain observatories by the appropriate entities, so that we may continue to have access to climate information from the ’tops of the world‘.