DAN COGGIN has spent most of the past seven years observing turmoil in Asia--grim but invaluable experience for his latest assignment, this week's cover story on Pakistan. A former Marine, Coggin witnessed the Indonesian crisis of the mid-'60s, went next to South Viet Nam and then served as New Delhi bureau chief. Assigned to the Beirut bureau last fall, he continues to contribute his expertise on Pakistan. He was one of the 35 newsmen expelled from Dacca on March 26, but in April he trekked from India by oxcart, rowboat, motorcycle, bicycle and bus to become the first American journalist to get back to the Eastern capital. He returned again for this week's story and, despite his having seen much war in the past, found that "this one has special horrors."

The two other correspondents contributing to the cover story are also veteran observers of Asian fighting. James Shepherd, an Indian national, joined TIME'S New Delhi bureau in 1958. His assignments have included India's border clashes with China and the Indo-Pakistani war waged over Kashmir. Recently Shepherd toured the refugee camps that line the Indo-East Pakistani border. David Greenway, whose most recent beat was the United Nations, formerly served in the Saigon and Bangkok bureaus. Last week he visited the insurgent forces. "The countryside," he says, "looks quite like Viet Nam, and with all the airpower, armor and artillery the rebels face, it must have been like visiting the Viet Cong in the early days of that other war."

Our essay this week deals with imaginary numbers, those intriguing but often inadequately supported figures that festoon our data-happy society. Like other publications, TIME sometimes finds it impossible to avoid using such numbers. They are accurate as far as anyone knows, but inevitably they represent estimates rather than precise measurements. In the current issue, the cover story quantifies East Pakistan's essentially unmeasurable agony in several ways (more than 7,000,000 refugees fled to India, for example). Elsewhere we note that U.S. crops are annually dusted with "about 1 billion pounds of pesticide" (ENVIRONMENT), and that microorganisms once killed 100 million pounds of fish in Florida (THE NATION), confident that these figures represent at least reliable approximations. As a result of the Essay, continued watchfulness about imaginary figures will be pledged by nearly 200 TIME editors, writers, reporter-researchers and correspondents. At least that is our estimate.

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