Dr Gear Guy, please realize that you are completely indemnified from any liability as to the efficacy of your answer, but I'm wondering what gear you'd specifically recommend for a hiker who has undergone a total hip replacement and refuses to cast a deaf ear to the call of the wild? I have a pair of good trekking poles. Anything else come to mind? Keith Columbus, Ohio

Andean Adventure The Sacred Valley November 11, 1997 The architecture of the ruins was years ahead of its time To the Incas, the idea that one valley is more sacred than any other may have seemed strange. The natural world formed the basis of their worship:…

You better grab a lifeline and hold on tight when Steve Fossett decides to make another manic bid for glory

Forget space aliens and serial killers—the latest movie monster is global warming

I'm in search of a three-season sleeping bag for under $350 that is down-filled, is rated to about 15 degrees, weighs under three pounds, has a durable weatherproof shell, and includes a full-length zipper. I was going to buy the REI Sub Kilo but all the reviews say it rips easily. I've been considering the Mountainsmith Vision, the Mountain Hardwear Spectre SL, and the Marmot Hydrogen, too, but can you help me narrow the field? Philip Berkley, Massachusetts

What's the difference between a bivy bag and a tent? Which would be a better investment (I'm thinking of room for two people here)? Noel Muscutt Louisville, Kentucky

I've been out of ice climbing for a few years now and wanted to know your thoughts on the lightest, warmest mixed- and ice-climbing boot. I used to have trouble with keeping my heel down in the boot. Have today's boots improved on this? Ad Lansing, Michigan

Can you recommend a mid-sized backpack? I have been looking at the new Arc'Teryx Bora 65, which is nice but really expensive! Is there a comparable backpack for less? Petter Boulder, Colorado

As an all-over-the-place sleeper, I have a hard time sleeping in mummy-style bags. The stretchiness and light weight of the MontBell bags look great, but I also think I would like the NightCap feature on the Sierra Designs Flex bags, though these are much heavier. Do you think these "stretch" bags are just hype? Jeanette Tucson, Arizona

Can you recommend good gear to start a beginner fly-fisher (at a reasonable cost)? Kristi Charlotte, North Carolina