SLITHERING SOUTH: by Steve Van Beek. Hong Kong: Wind & Water, Inc., 2001. 430 pp. with map and glossary, $11.95.

Sliding (or bumping) down the shallow Ping River, the long tributary that joins the Chao Phya and flows through Bangkok, Steve Van Beek pondered his odyssey. Having begun in the river's headwaters near the Burmese border, he had paddled from the still-natural north into the polluted south, rested on his oars midstream and realized that "I was more interested in the journey than in the destination."

During his nearly two-month, 1,120-km journey from the Golden Triangle to the Gulf of Thailand, a distance a plane could have covered in an hour, the intrepid foreign boatman had ample time to consider the implications of his voyage.

He wanted, he knew, to travel like the early Thai river men, "slipping into the jungles or villages and eating local food," and he wanted to find out what happened to the river, for it is quite dead by the time it reaches Bangkok. But perhaps an even greater charm was the quixotic nature of the venture, its luxurious uselessness, and the tests that came with it.