''Living With Inflation'' (1980), ''Growth in a Conserving Society'' (1978): once- dominant concerns seem, in retrospect, dated and sepia-tinted, the more so since participants in the annual public affairs encounter seem never able to avoid the sort of apocalyptic pronouncements which so quickly age.

This year's conference, the 54th such gathering of experts and laymen in the woods north of Toronto, was once again overshadowed by a heavy sense of crisis. We are, the 250 delegates were regularly and briskly informed, living at a time of profound crisis, of hard choices, of painful reappraisal.

But then, crises are Couchiching's stock in trade, and though the official question for debate was ''Who in the World Needs Canada?'' what emerged during the four-day conference was an urgent search for Canada the world leader - partly out of nostalgia for the postwar days when a rich young nation, spared the ravages of war, could wield disproportionate influence, and partly out of an uneasy sense that if we do not seize the day now, the world may soon pass us by.

NUCLEAR ANNILHILATION

Of course, as crises go, you can't do much better than nuclear annihilation. Hence, at a conference in which delegates regularly prefaced statements with remarks like: ''If we do survive the next 20 years . . .'' the popularity of keynote speaker Gwynne Dyer could be expected.

A renowned military and international affairs expert, Dyer's concern is to disentangle us from alliances he considers purposeless, even dangerous - Nato and Norad.

It perplexes him that, almost alone among Western hemisphere nations, Canada continues to maintain troops in Europe, even though we face no direct threat of attack from the Russians. And, he warned, with the coming unification of offensive and defensive command structures in the U.S., the traditional Canada-U.S. joint command over air defense will become obsolete.

What to do? From a range of unpleasant options, Dyer proposed perhaps the least palatable: Finlandization. That is, leave the alliance, but allow the Americans to use our territory in their defense.

Quite what this timorous disengagement from reality would accomplish Dyer was unable to say, but the delirium tremens a pullout from Nato would induce in the West Germans could hardly do more to destabilize the European situation, as Charles Doran of the Centre of Canadian Studies at Washington's Johns Hopkins University noted.

International trade provided a more hopeful arena for Canadian initiatives. Interestingly, debate centred less on the merits of free trade than how to achieve it, and with whom, and on what schedule.

The strongest runner currently is bilateral free trade with the U.S., which clearly had the support of Royal Commission on the Economy Chairman Donald Macdonald and, later in the conference, External Affairs Minister Joe Clark.

With U.S. protectionist sentiment rising even as demand for Canadian resource exports is falling, Macdonald stressed that we must gain guaranteed access to a trading area of at least 100 million people, which means some sort of bilateral arrangement. We cannot wait, Macdonald said, for a multilateral pact - the last international round of tariff cuts took 12 years to negotiate.

That, a cynic might suggest, was precisely why former United Steelworkers of America official Don Taylor favored the multilateral approach. As usual, the ''public interest'' was invoked to warn of the hideous dangers of free trade with the U.S. Never mind job dislocation, forget traditional ways of life, a bilateral trade arrangement with the U.S. would jeopardize ''the existence of Canada as a sovereign nation.''

But Taylor did call for a ''trade arrangement'' with the developing countries, and a first step might be the elimination of our shameful tariffs against textile imports, the most obnoxious form of anti-aid to the Third World in which we indulge.

Competitive exports were the name of the game for telecommunications market analyst Francis McInerney, president of Northern Business Information Inc., New York. Beneath a few layers of business-speak, McInerney's message was refreshingly blunt: Canadians should stop moaning about their problems and start getting nasty in export markets, driving prices through the floor and scaring hell out of the competition.

McInerney was one of several speakers to emphasize the advantages we have in international competition. Our vast spaces and scattered population have forced us to develop a telecommunications technology that is the envy of the world. Our workforce, well-educated and money-motivated, is ideally suited to the high- technology industries of the future. And our ethnic makeup means we have people who speak ''the languages of our markets.''

In the Far East, the opportunity to put these advantages to work are there for the taking. But Charles McMillan, senior policy adviser to the Prime Minister, warned we are in danger of missing the chance to establish a special relationship with the industrializing Pacific Rim nations, just as we missed it a generation ago with the Japanese.

We are well-known and well-liked in the Far East, or the ''Near West,'' as Alcan Aluminium Ltd. Vice-President Eric Trigg preferred, and our expertise lies in areas they need, chiefly infrastructural sectors. And, contrary to the gospel of high-tech, much of our potential sales to these nations will come not from state- of-the-art wizardry, but from basic, secondary technology - cheaper and more immediately applicable.

FOLLOW OUR LEAD

From Asia, where the focus was on exports, attention turned to Africa, and foreign aid. But how were we urged to help the African nations? By teaching them to follow not the American example, as the fast-growing Asian countries have done, but our own more dirigiste model, as they by and large have done.

Ottawa Citizen Editor Keith Spicer, a founder of Canadian University Service Overseas, called for foreign aid to be based on ''less capital and more ideas.'' Fair enough, and his proposal for radical surgery to the Canadian International Development Agency was well taken, but the biggest of his ''ideas'' was the Canadian economic system - not here considered as the accrued legacy of hasty solutions to vaguely understood problems, but as a distinctive ''middle way.''

There it is - Canada's instinctive worship of anything neither fish nor fowl, now raised as a standard for other nations to follow. We could show the Third World, Spicer said, that the ''wild, ugly excesses of capitalism'' need not accompany a private- enterprise system.

Going the other way, Gloria Nikoi of Dalhousie University's Pearson Institute for International Development suggested that we could show the Americans that large-scale intervention in the economy does not necessarily mean socialism. We have, she said, a special understanding of Third World problems. Indeed we do.