An extract from a tribute written by Jim Gregson for the Karabiner Mountaineering Club
From 1946 onwards, Dennis had amassed a huge range of experience in the UK and the European Alps, but he also had the drive and ambition that allowed him to make his mark in the Greater Ranges. He had tried to get a place on the expedition which made the first ascent of Kangchenjunga but this was not to be. Instead, Dennis went in the same year, 1955, to the Rolwaling Himal where in a single lengthy trip his expedition team made first ascents of no less than 19 peaks of 20,000 feet altitude. In 1957 he went back to altitude in Nepal on expedition to Annapurna IV with Charles Evans and then to Distaghil Sar.