Aconcagua. Fine weather permitted us to climb Aconcagua by the regular north-slope route in four days from Base Camp at Plaza de Mulas (14,000 feet). No one suffered from altitude sickness thanks to our program of acclimatization: Day 1: by train to 9000 feet; Day 2: rest; Day 3: hike to 13,000 feet and back; Day 4: with mules to Plaza de Mulas; Days 5 & 6: rest at 14,000 feet; Day 7: carry to 18,000 feet and back; Day 8: to 18,000 feet (Antarctica Hut); Day 9: to 20,250 feet (Berlin Hut); Day 10: to summit and back to Berlin Hut; Day 11: to Plaza de Mulas. Miguel Alfonso, Stuart Frank, Jon Haake and Tom Cole reached the summit on March 5. Sandy Bryson had to turn back 300 feet from the top and I accompanied her. The others reached the summit four hours later. They descended in the darkness, lost their way and did not reach the Berlin Hut till 10:30 P.M., barely avoiding an unplanned bivouac. Minimum recorded temperature was -22° F at 20,500 feet. The Argentine army, which controls access to the mountain, requires lengthy procedures: equipment check, cardiac examination by a local physician, blood-type tests, a climbing résumé from each member including high-altitude experience, a complete police dossier with mug shots and 8 sets of fingerprints, a $10 “rescue” deposit from each climber. Without “inside” help, future expeditions may well be stranded in Mendoza for a week or more.