"If future generations are to remember us with gratitude rather than contempt, we must leave them more than the miracles of technology," Johnson said. "We must leave them a glimpse of the world as it was in the beginning, not just after we got through with it."

The signing of the Wilderness Act came after eight years of debate, congressional hearings and revisions to its language. It passed the Senate in 1961 and the House in 1964. Johnson's signature immediately designated 54 wilderness areas covering more than 9 million acres in 12 states, including the Superstition Wilderness in Arizona and the Frank Church/River of No Return Wilderness in Idaho. The law also marked 34 additional areas as potential wilderness to be studied.

Today, there are 662 separate areas designated as wilderness by Congress, covering a total of 106 million acres.

"The passage of the Wilderness Act . . . was the single most permanent, sweeping sort of legislation that maybe Congress has ever passed. Not just environmental, but ever passed," said Dick Carter, a former forest ranger, current leader of the High Uintas Preservation Council and longtime player in Utah's wilderness battles. "It changed our imagination. It changed our collective view of land.

"In 1964," he said, "it had no end in sight."

The seven relatively brief sections of the act defined "wilderness" as federal land retaining its "primeval character and influence . . . affected primarily by the forces of nature, with the imprint of man's work substantially unnoticeable," and made Congress responsible for adding more land, when it desires, under that definition. [See accompanying box for the language of the bill].

Wilderness Act facts

4.7 percent of America's landmass is permanently protected as wilderness.

Democratic presidents have signed wilderness bills protecting a total of 85,700,000 acres; Republican presidents have signed bills protecting 19,800,000 acres.

President Reagan signed 43 wilderness bills during his tenure. President Carter signed 14 during his four years in office.

There are 44 states with designated wilderness areas, and 20 states with current wilderness bills or proposals.

There are 9,078,675 acres in the largest wilderness area, Wrangell-St. Elias in Alaska; there are only 5 acres in the nation's smallest wilderness area, Pelican Island in Florida.