GETTING THERE: Alia, the Royal Jordanian Airline, flies daily from June through September, and five days a week from October through May, from New York to Amman via Vienna or Amsterdam. The current round-trip APEX fare is $771 ($881 for peak season, June 20 to July 31), with a stay of from six days to two months. Special rates for tour packages to Petra are available for those booking on Alia.

British Airways, Lufthansa and Air France also have several weekly departures to Amman from London, Frankfurt or Paris, connecting with their flights from New York. The same APEX fares apply, but the minimum stay is seven days on Lufthansa and Air France. Visas are required for all foreigners, and while these usually can be issued to Americans at Amman airport, Jordan advises that the documents be obtained through its embassies before departure.

WHEN TO GO: The high seasons for travel in Petra are from March through May and from October through December. Temperatures in July and August, the hottest months, can reach into the high 80s (a hat is essential), but the ruins can be visited at any time of year. While the sun is strong at noon, a sweater may be necessary in the evening even in June. Christmas and Easter in Petra are usually heavily booked far in advance.

GETTING AROUND: JETT bus tours to Petra and other cities leave daily from most major hotels in Amman. The tours can be booked at the front desk the day before you wish to go. Visitors taking the full-day tour usually are picked up around 6:15 a.m., spend about four hours at Petra and return to Amman in the late afternoon. Cost of the guided tour with lunch is $55 per person.

The route across the newly constructed Desert Highway is rather boring (oil trucks, tour buses and very little scenery other than an occasional tribe of nomads herding their sheep). Two hours into the trip, the buses always make a rest stop at a roadside cafe' for tea and souvenirs, or perhaps a light breakfast of bread and labneh (yogurt cheese).

If you want to avoid the bus tour, have a longer stay in mind and decide to rent a car (you can also rent a taxi seating four), follow the older, more picturesque King's Highway.

Plan to arrive at Petra in the afternoon. You can hire a guide and horse the next morning at the Tourist Center just around the corner from the Forum Hotel. (You can walk into Petra, but a guide will make your first visit easier and you will become oriented more quickly.) The quality of the guides varies and there is no set charge, so negotiate the price before setting off.

There is no admission charge if you walk into Petra. If you ride, the use of a horse costs about $5 and that includes your admission fee (the ticket is good for re-entering in the afternoon).

WHERE TO STAY: Amman offers a wide choice of hotels, including the Amman Marriott, Jordan Intercontinental, Holiday Inn, Regency Palace and the Jerusalem International. Daily rates range from about $40 to $95 double.

At Petra, there are two choices: The Jordanian-run Guest House or the Forum Hotel. Both are near the village of Wadi Musa' and only a short walk to the Siq.

The 40-room Guest House, built into the side of a mountain, has no frills but provides private baths. Rates are $28 double with breakfast.

Or, for those in search of more creature comforts, a swim to break the heat's midday hold and a romantic setting, the 2-year-old Forum Hotel is the answer.

Carved out of the native sandstone and set unassumingly in the middle of superb vistas, the 82-room Forum offers Middle Eastern and international cuisine and poolside service for its guests. The hotel is owned by the government but operated by the Forum Group and managed by Bill Trustram Eve, an Englishman with a taste for archeology. Eve is an excellent source of information on the area.

Rooms run about $68 a night double, with breakfast. But anyone, guest or visitor, can make use of the veranda and orange juice and aperitif bar to watch sunsets over Petra. Reservations are a must. Christmas and Easter are generally booked solid -- often a year in advance. To reserve a room, see a travel agent or your airline.

SIDE TRIPS: While Petra is worth a trip in itself -- and no visit to Jordan is complete without exploring the lost city -- the country has other treasures.

The scenic drive back from Petra to Amman by the King's Highway is longer than via the Desert Highway but provides a more memorable experience. There are Crusader castles at Shobak and Kerak, the Byzantine mosaics at Ma'daba and Mount Nebo; and further north lies the Roman city of Jerash. Amman itself, with a history that goes back 3,000 years, is now a modern capital with broad streets, shops, government buildings, gardens and villas.

INFORMATION: Jordanian Information Bureau, 1701 K St. NW, 659-3322, or Alia, The Royal Jordanian Airline, 857-0401.