More than 150 years ago, Henry David Thoreau wrote his book "Cape Cod," to reflect on the "other" world he found in the unspoiled beaches and ocean surf along the bent-arm-shaped peninsula that continues to draw visitors the way the moon does the tide.

While Cape Cod today is better known as a busy, traffic-congested, overdeveloped and overcrowded seaside sprawl, there still exists a 40-mile stretch of protected beaches that reflect the original, more beautiful side Thoreau celebrated.

Cape Cod National Seashore begins in Eastham, Mass., at the cape's elbow, and extends to the "fist" in Provincetown, Mass. Along this stretch, there are five ocean beaches and one bayside beach that make up the cape's protected national seashore, which was established in 1961 by the Interior Department. Preservationists, environmentalists and those who look forward to stretches of nothing but sand and the rhythmic ocean cadence are willing to drive the extra hour, not only to enjoy the less frantic and more relaxed beaches of the cape but also to take advantage of the assorted venues that offer great surfing, fishing, swimming, beachcombing and sunset viewing.

COAST GUARD BEACH

The southernmost of the beaches, Eastham's Coast Guard Beach, is one of the busiest and most easily accessed on the national seashore chain. While able-bodied visitors must park at a nearby school (and use the park's shuttle system to get in), once there, it is an easy walk down a gently pitched ramp to the beach. Handicapped parking and special beach-friendly wheelchairs are near the ramps.

"The shuttle is part of the adventure," said Sue Moynihan, chief of interpretation and cultural resources at the national seashore, noting that Coast Guard Beach is considered one of the top 10 beaches in the United States. There are about 500 off-site parking spaces, so be prepared: On nice days, the beach is crowded until midafternoon.

Beyond the sand, which has areas for pets and night campfires (permits required), Coast Guard Beach houses a refurbished 1930s former Coast Guard station, now an education center. Surrounding the park is a salt marsh and a walking/biking trail that connects the beach to information at nearby Salt Pond Cape Cod Visitors Center.

The beach made international news about 15 years ago when a series of storms caused serious coastal erosion, uncovering a prehistoric cooking hearth. Archaeologists converged on the site and unearthed other fire pits, pottery and artifacts believed to be from American Indian camps 4,000 years earlier.

"History comes alive here," said Moynihan, noting that while the ocean water is colder and wilder when compared with the bay side, low tide does allow beachgoers to walk out to a series of sandbars.

NAUSET LIGHT BEACH

Go just a mile or so north along Nauset Road and you'll find the second national seashore site, Nauset Light Beach, considered one of the most scenic of the oceanside beaches.

"The appeal is the lighthouse," said Moynihan, referring to the working lighthouse, which several years ago was moved back after beach erosion threatened to topple the landmark.

Nauset Light Beach is the most popular and usually the first to fill up on sunny days. Its 175 on-site parking spaces are often gone by 10 a.m. A pretty, steep staircase (which seems even steeper as you try to wind your way down balancing a cooler, a couple of beach bags and an umbrella) takes you down to the beach, which also has areas for pets and campfires.

Free tours of the lighthouse are Wednesdays and Sundays from 4 to 7 p.m. If you are in the mood for a stroll, the Three Sisters Lighthouses — three small, wooden lighthouses that are no longer active but are under park ownership — are nearby.

MARCONI BEACH

Continue north to historic Wellfleet, where the beach was named for Guglielmo Marconi, the Italian inventor who completed the first trans-Atlantic wireless communication system between the United States and England, in 1903. The beach area also was the site of a World War II artillery training facility.

Now considered a great place to surf and fish, Marconi Beach is one of the national seashore's largest beaches, with more than 550 parking spaces just a short walk from the ocean. Here you will find some of the cape's greatest sand dunes and a 40-foot-high sand cliff — but no climbing. Only looking is allowed.

HEAD OF THE MEADOW

Continuing north, Head of the Meadow beach in Truro offers seclusion and beauty along Route 6. The glacial cliffs/sand dunes of the outer cape reach their highest here, exceeding 100 feet in some spots. Miles of continuous sand beaches remain largely undisturbed and undeveloped. The beach is a popular spot for families and others who take advantage of nearby camping facilities. Swimming and wading are popular here because of the numerous sandbars, and wave action provides some of the best body-surfing along the national seashore. Park officials say low tide reveals remains of shipwrecks that occurred near the banks of the outer cape.

RACE POINT

You're nearing the end of the line as you approach Race Point, where, with a permit, you can drive onto the beach. Considered one of the best locations for surf-fishing, Race Point, just beyond the Provincetown Airport, has ample parking and is usually one of the last of the national seashore beaches to fill up, meaning it tends to be quieter and less crowded than others. This is the place to go for spectacular sunsets and whale-watching, bicycling or just meandering along the beach.

Be prepared for pockets along the beach to be closed so that the endangered piping plovers can safely nest.

HERRING COVE BEACH

If crashing waves aren't your thing, then head to this beach, the only bay-side beach that is part of the national seashore. Warmer, quieter water; beautiful sunsets; a concession stand; and the proximity to town make this a popular destination. This end of Herring Cove can be accessed from the parking lots or from Herring Cove Trail, a foot trail that crosses a series of dunes and high-tide inlets known as The Moors. Off-road permits are available for this beach from the ranger station at Race Point.