The Washington region is a 20th-century white-collar boom town that exploded outside the District of Columbia after World War II in a largely unplanned and almost unseemly rush. Developers' bulldozers, in panzer-corps blitzkriegs, leveled farms and woods surrounding the Nation's Capital. Subdivision homes sprouted row after row like corn crops. Shopping centers and interstate highways appeared in the middle of pastures.

Then, somewhat belatedly, residents began thinking about parks.

Few parks existed for recreation. But then, there was little organized recreation before the 1960s and there seemed little need for open space when there were wheat fields and dairy farms within 10 miles.

Northern Virginia had almost no local public parks and no state parks. Those that exist today were largely acquired in a frantic and expensive last-minute buying spree in the 1960s and 1970s, primarily by the newly formed Northern Virginia Regional Park Authority and the Fairfax County Park Authority.

In Montgomery County local and state officials have been buying park land for 50 years, much of it under the 1930 federal Capper-Crampton Act, which created the George Washington Memorial Parkway and offered matching grants to Virginia and Maryland to create stream-valley parks. Virginia was not interested, but Montgomery County used the act to build by far the area's largest local and state park system, protecting and preserving virtually every stream valley in the county.

Some of the Washington region's most scenic areas are federal park land. The two largest and most beautiful close-in parks are Rock Creek, established in 1890 as the nation's first urban federal park, and the George Washington Memorial Parkway, built in 1932. Other federal parks were formed from Civil War battlefields, abandoned forts and surplus land from other federal agencies: Manassas, Antietam, Monocacy, Fort Washington, Catoctin Mountain, Prince William Forest, Greenbelt and the C&O Canal, and the many little fort parks around the city.

Given today's confusing jumble of area parks, run by almost a dozen local, regional, state and federal park agencies, it is often difficult for residents to learn what parks are here and how to find and enjoy them.

Last year, Alan Fisher, a veteran of "walking" books for Boston, Baltimore and Philadelphia, published "Country Walks Around Washington," which showed how to get away from the city at 20 nearby parks that hikers could reach by public transportation. Now, his sequel, "More Country Walks Near Washington," goes farther afield with another 18 walks, most of them two to six miles in length, and almost all less than an hour's drive from Washington.

At Maryland's Calvert Cliffs State Park, Fisher focuses on shark teeth from the Miocene epoch and how to look for 20-million-year-old fossils at the base of the cliffs.

At Fairfax County's Dranesville District Park, just north of the Cabin John Bridge, he describes what he calls "some of the best scenery and walking near Washington" and recounts -- as a case study in park acquisition -- the acrimonious history of the 336-acre park, which developers wanted to subdivide for 309 houses. After reading his account and taking a three-mile hike to a waterfall and the Potomac Palisades, he writes, "you may want to consider how you would have sided in the controversy and what, if anything, you are willing to do for the preservation of similar areas in your own community."

On one of three walks on both sides of Great Falls, Fisher notes the potholes in rocks more than 60 feet above the churning waters. "Such potholes, of course, are worn by cobbles that swirled in eddies at the bottom of the river" some 2 million years ago when the river was higher and the ocean covered much of Maryland and Virginia. Fisher gives a brief and interesting Geology 101 account of how Great Falls came to be. Fisher's best-described hikes are the battlefield walks across some of the bloodiest ground of the Civil War: Antietam, Maryland Heights (at Harpers Ferry) and Manassas National Battlefield, now among our most peaceful rural parks.

"More Country Walks" tells which parks you can walk your dog in (on a leash); describes the scenic wonders; maps the trail difficulties caused by the geologic formations you are climbing over; and discourses on the passing flora, noting, for example, that the eastern red cedar, "actually a juniper but commonly called a 'cedar' is a short-lived species frequently found in overgrown fields."

This is a jolly good guide to stick in the pocket of your shorts when hiking in the Washington area.