RESOURCES: Former inner canyon ranger Denise Traver maintains a comprehensive and invaluable Web site for Grand Canyon hikers, www.hitthetrail.com. "I started the Web site because I saw the trouble people got into," she said. "It's not a commercial site (indeed, there are no ads), it's to help people out." The information is so comprehensive here that you'll even get tips for how to lace your boots for a downhill trail so as to reduce the pounding on your toes.

Park service hiking advice can be found at www.nps.gov/grca/backcountry/tips.htm. Two helpful guidebooks, both available in stores at the rims, are "Hiking Grand Canyon National Park" (Globe Pequot Press; $14.95) and, if you're interested in flowers, geology and critters, "A Field Guide to the Grand Canyon" (The Mountaineers; $19.95).

GEAR: Do yourself an enormous favor and don't cut any corners when buying equipment. There's a reason the stuff at big discount houses is so cheap. You'll be sore from head to toe when you finish this trek anyway; do you want to compound that discomfort because of inferior gear?

To begin with, lighten up. Today's miracle fibers and materials can combine support and comfort without packing on extra weight. The Granite Gear Vapor Trail pack I picked up is 2 pounds, 5 ounces when empty, yet is generously padded and conforms nicely to the body. Merrell boots provide good ankle support despite being light (1 1/4 pounds each), and don't require extensive breaking in.

Trekking poles reduce the abuse of your knees, especially on long downhill stretches, because some of the strain is absorbed into your arms and shoulders. Elastic knee sleeves help, too. And here's a revelation, found on Traver's Web site: Stop by a dance supply store to get the toe pads that ballerinas insert into their slippers. It might avert the loss of a toenail or two.

Rangers are also unanimous in the admonition to carry as little weight as possible to reduce the strain on your body. Most of the weight in your pack should be food and water, with only the bare minimum of clothing and toiletries. We talked with some hikers who did a load of laundry at the South Rim so as not to carry extra clothes.

Get high-tech socks that wick moisture away from your feet, but as for outer wear, forget about miracle fibers and wear good old cotton, because it will stay wet when you dunk your hat and shirt into a stream and wear them for evaporative cooling.

WHEN TO GO: The best time for hiking the Grand Canyon is the fall, when the temperatures are cooler. Plan your trip for October if you can arrange it. Avoid the dead of summer. We aimed for May, arriving only a few days after the North Rim lodge ended its winter hibernation, and still encountered a Southwest heat wave 85 degrees on both rims and well into triple digits on the canyon floor.

WATER STRATEGY: This is tricky. You'll want to carry plenty of water in the canyon, of course, but that water also means extra weight in your pack. So check with the rangers at the visitors centers in advance to find out where piped drinking water is available, then plan on carrying what you'll need between these stops. In the early morning, for example, you might need only a couple of liters for the 1 1/2-mile stretch from the North Rim to Supai Tunnel, where you can top off again. But from Cottonwood Campground to Phantom Ranch in the late morning seven waterless miles in full sun you will want three to five liters per person.

WATER AIN'T ENOUGH: Your body needs fuel. It also needs to replace the salts you lose through perspiration and you'll sweat copiously in the inner canyon heat. Staying hydrated is critical, of course, but if you guzzle water without eating anything, you can be felled by hyponatremia water intoxication which can be every bit as debilitating. This condition can be staved off by consuming electrolyte drinks (Gatorade and its equivalents). This can be purchased in powdered form and mixed at the water stations. In lieu of this, at least eat salty snacks at frequent intervals on the trail.

BEDDING DOWN: Lodging is limited at Phantom Ranch, and demand for it is extreme. Until recently, park concessionaire Xanterra maintained a reservations window of 23 months, but it will shorten that to 13 months come Sept. 1 meaning bookings can be made then for October 2006. Full payment is required by credit card when you book your stay. Information can be found at www.grandcanyonlodges.com (a somewhat balky Web site), but reservations can only be made by phone: (888) 297-2757.

Last-minute cancellations sometimes occur at Phantom Ranch, so if you want to try to snag a reservation on a same-day or next-day basis while in the midst of your trip, contact the Bright Angel Transportation Desk, which keeps a waiting list: (928) 638-3283.

Accommodations at Phantom Ranch include cabins with bunk beds and dormitories, and showers are available at a central location. Be sure to book your meals dinner, breakfast, sack lunch at the time you make your reservation.

Bright Angel Campground is another option, but that, of course, means lugging cooking and sleeping gear.

If you're hiking from the North Rim to the South Rim, consider getting a cabin at Bright Angel Lodge on the South Rim. It is literally at the mouth of the trail, and when you complete this trek, you won't feel like walking any great distance to get to your room.

SHUTTLE: To get back to your car on the other side of the canyon, reserve in advance a ride on the Trans Canyon Shuttle: (928) 638-2820. It takes off from the North Rim each morning at 7, and departs the South Rim each afternoon at 1:30. The cost is $65 per person.

The ride is a long haul around the east side of the Grand Canyon 215 miles in all, requiring five hours but the ride is scenic, taking in viewpoints of the South Rim, the Little Colorado Gorge, the Vermillion Cliffs and the lushly forested Kaibab Plateau. And would you rather walk back through the canyon?

GUIDED TOUR: We took this hike independently, but if that is a daunting prospect, consider hooking up with one of the outfitters that leads groups from rim to rim. We were impressed with the guides we met from one such company, the World Outdoors, which offers six-day excursions from Flagstaff for $2,095 per person, double occupancy. www.theworldoutdoors.com; (800) 488-8483.

IT'S NOT A CONTEST: If you take your time, rest frequently in the shade and avoid the heat of midday, you'll enjoy this hike infinitely more. Ken Phillips, who heads rescue operations for the park service here, said, "Oftentimes, when folks develop problems within a group they have a weak member believe it or not that person gets left behind. The rest of the group needs to take the load off them." Let that person lead, and if that means a plodding pace and a rest stop every 20 feet or so, well, there are some great views to savor.