Moab's towering cliffs and deep canyons can be intimidating and unreachable without the help of a guide. Fortunately, guide services are abundant in Moab, whether you are interested in a 4x4 expedition into the rugged backcountry, a river-rafting trip, a jet-boat tour on calm water, bicycle tours, rock-art tours, or a scenic flight. It's always best to make reservations, but don't hesitate to call if you make a last-minute decision to join an expedition. Cancellations or unsold spots sometimes make it possible to jump on a tour with short notice. One notable exception is the Fiery Furnace tour in Arches National Park: book at least one month in advance!