What the heck is an R5B? A C4? An M1? If you've ever looked at a zoning map, you've probably asked such questions. Zoning codes are almost always an enigmatic jumble of letters and numbers that only a land-use lawyer could love.

In New York City, zoning just became a little less mysterious. The city's planning department recently published a new zoning handbook that translates New York's monstrous code into a series of photographs, diagrams and plain-English descriptions. An R5B, it turns out, is a stately row of three-story townhouses.

The zoning handbook doesn't make the underlying code any simpler. But it does make it easier for New Yorkers to understand what can and can't be built in their neighborhoods.

For excerpts go to http://www.nyc.gov/ html/dcp/html/pub/zonehandc.shtml