ERIC Langmuir has died peacefully of cancer at his home, Clach Mhor near Aviemore, aged 74. He had been ill for only a very short time, having apparently recovered completely from cancer three years previously. In fact, only four weeks before his death he was walking vigorously for three days over the roughest Lakeland fells, a weekend which he described as the best ever of many such outings.

That was typical of the man, leading mountaineer, topgrade ski instructor, orienteer extraordinary, sailor, teacher, environmentalist and author.

There was little, if anything, in the outdoor activities field which he did not influence substantially in a lifetime of personal achievement and enjoyment on the mountains and the sea. His book Mountaincraft and Leadership, known to many simply as "Langmuir", painstakingly revised by him over the years, has become the classic work for all those in any way involved with taking groups on to British hills or simply aspiring to climbing them themselves. It is not just an essential textbook, it is a highly readable and enjoyable guide to all aspects of the mountain scene.

Born in Glasgow, Eric was educated at Fettes College and Cambridge University, where he read geology. It was at Cambridge that he blossomed as a climber, becoming president of the University Mountaineering Club and, with an ever increasing number of kindred spirits, successfully tackling some of the hardest British and Alpine routes. Among many fine new climbs he pioneered as a leader in Scotland, Spartan Slab in Glen Etive still ranks as an outstanding expedition, to be treated with great respect.

After graduating and working for a short time as a geologist in Canada, he became a school teacher but was soon asked by Jack Longland, Derbyshire's director of education and Everest climber, to take over the principal's job at the county's outdoor pursuits centre, Whitehall.

It was there that Eric made his distinctive mark as a leader among fellow enthusiasts, able to instil knowledge and appreciation of the outdoors among staff and pupils alike. There were always climbers eager to support him voluntarily in his work so as to complement the vital contribution of the core of permanent staff. Such was Eric's own enthusiasm and magnetism.

When the principal's post at Glenmore Lodge, Scotland's national outdoor centre, became vacant, Eric was the obvious candidate and for seven years he presided with great success over an ever-more-popular and important establishment.

Those who worked with him then in any capacity look back with enormous satisfaction to a uniquely rewarding experience.

He was at pains to improve his own skills in other aspects of mountain activity than climbing and became a highly proficient skier and instructor, attaining the highest grade of the British Association of Ski Instructors.

It was typical of the man that he established close working relations with this professional body as he did with all those other national organisations concerned with outdoor activities, whether it was, for example, canoeing, sailing or orienteering, the last of which was to become a passion in his retirement years. In his time the lodge became a "Mecca" for all lovers of the outdoors.

Mountain rescue was an important element of the lodge's responsibilities and, typically, Eric entered into this vital aspect of mountain activity with his customary enthusiasm and determination, becoming chairman of the Mountain Rescue Committee for Scotland and studying avalanche avoidance and rescue techniques with the late Andre Roch in Switzerland. Many years later he was to be asked to set up Scotland's first avalanche warning programme to give guidance to all those venturing on the mountains in winter.

Moray House College in Edinburgh, one of Scotland's premier teacher-training establishments, decided to recruit an outstanding practitioner to establish and develop courses at all levels of outdoor education and Eric was prevailed upon to move to a new career, though still closely concerning students and teachers. Over a period of years Eric built up this new department, recruiting gifted staff and ensuring that all those wishing to come to the college had an opportunity to participate, at a chosen level, in the field of outdoor education.

It was only when, in 1976, following local government reorganisation in Scotland, a new department of leisure services was created in Lothian region and Eric was persuaded to join it as an assistant director responsible for all countryside matters. These included Hillend Ski Centre, probably Britain's largest artificial ski centre and ski training establishment and, eventually, Port Edgar, a new marina and sail training establishment on the Forth. But Eric involved himself in many more new projects, such as Countryside Awards, a grants scheme to encourage young people to become involved in the local environment, and the setting-up of the Pentland Hills Regional Park.

After further local government reorganisation brought about the closure of the department in 1985, Eric continued to work in the region until his retirement in the planning department still concerning himself with many of his previous responsibilities.

Ever since its formation in 1964, Eric had been a leading member of the Scottish Mountain LeaderTraining Board and was asked to initiate and edit a new handbook for all those taking part in the board's schemes.

This book, honed and much added to over the years, became the official handbook for all the UK Mountain Leader Boards and, eventually, the reference book for mountaincraft in general, a tremendous achievement which will be a lasting memorial to Eric's contribution to recreation on the mountains. In retirement, from his new home beside Avielochan with glorious views to the Cairngorms, he became closely involved with the Countryside Commission for Scotland, acting as a regional member with a significant input into the eventual foundation of the Cairngorms National Park. Orienteering became his favourite leisure activity and, with his devoted partner, Marion McCormick, he participated for his club with enormous enthusiasm and much success in events at home and throughout the world and organised major events near his home.

For his contribution to mountain rescue, Eric was appointed MBE. For his contribution to the scientific aspects of mountain activity and exploration he was elected a fellow of the Royal Society of Edinburgh. His wife, Maureen, died of cancer more than 20 years ago and he is survived by their four children, two sons and two daughters, and eight grandchildren, and by his partner, Marion.

Eric Langmuir, mountaineer;

born May 3, 1931, died September 18, 2005.