THE JUNGLE IS NEUTRAL makes The Bridge Over the River Kwai look like a tussle in a schoolyard. F. SPENCER CHAPMAN, the book's unflappable author, narrates with typical British aplomb an amazing tale of four years spent as a guerrilla in the jungle, haranguing the Japanese in occupied Malaysia. Traveling sometimes by bicycle and motorcycle, rarely by truck, and mainly in dugouts, on foot, and often on his belly through the jungle muck, Chapman recruits sympathetic Chinese, Malays, Tamils, and Sakai tribesman into an irregular corps of jungle fighters. Their mission: to harass the Japanese in any way possible. In riveting scenes, they blow up bridges, cut communication lines, and affix plasticine to troop-filled trucks idling by the road. They build mines by stuffing bamboo with gelignite. They throw grenades and disappear into the jungle, their faces darkened with carbon, their tommy guns wrapped in tape so as not to reflect the moonlight. And when he is not battling the Japanese, or escaping from their prisons, he is fighting the jungle's incessant rain, wild tigers, unfriendly tribesmen, leeches, and undergrowth so thick it can take four hours to walk a mile. It is a war story without rival.