It is a sad but unavoidable feature of American life that politicians publish books. These fall into two genres, neither readable.

First is the memoir. Fat and airy, these books allow the politician, with fastidious attention to detail, to survey the vast panorama that has been his career and lie about it.Second is the policy treatise, a stringy little sausage with a title like "A Time for Commitment," in which the pol lays out what he sees as the Challenges of Our Time and lies about those, too.

The books are ponderous but nevertheless revealing - always inadvertently, sometimes horrifyingly. That's certainly the case with Sen. George Mitchell, who has recently weighed in with an overheated treatise called "World on Fire."

Most Americans familiar with the senator know him as Senate majority leader, decorous and bespectacled as he shuffles reams of wasteful and intrusive legislation on the Senate floor. But that's just by day. By night - and between the book covers - Sen. Mitchell is a zealot.

An environmental alarmist, to be precise. Not for Mitchell are the ambiguities of science. Most climatologists, for example, consider evidence of prognostications of extremists: boiling seas, beach fronts in the Mojave, the Netherlands at the bottom of the sea.

His discussion of acid rain ignores Congress' own $500 million study showing the problem to be much less severe than previously thought. His account of the ozone layer is similarly fantastic. And underlying the entire essay is a deep estrangement from the technology and economic freedom that have shaped American life.

"We risk turning our world into a lifeless desert in the coming century," he writes, "and bringing to pass the grim final environmental judgment of a world on fire."

This is pure apocalypticism, and it brands the senator a zealot as surely as if he strapped on sandals and a sandwich board and hollered from street corners. The millennium's end approaches, and we shall see many zealots in the next nine years. But it's a surprise to find one leading the United States Senate. Isn't it?