Backpacking in the Middle East. Wow! That聮s going to be interesting (I mean that in a good way).
Patagonia Silkweight T-shirt

I don聮t think any fabric on earth is going to keep you all that comfortable, but I聮d still vote for synthetics in most cases. You聮ll find they simply dry much faster than cotton, as well as being less inclined to develop and give off a bad odor when you聮re unable to do any laundry. And, I聮m completely convinced that fast-drying actually does help cool you through the evaporative cooling process.
So, yes, I聮d pack Patagonia Silkweight T-shirts ($32) and boxers ($26; www.patagonia.com). Also, you could try some items made with CoolMax ($20 at L.L. Bean; www.llbean.com). Ex Officio (www.exofficio.com) makes some excellent wicking, fast-drying underwear designed for hot, sweaty travelers. Briefs are $18, boxers $24, in several styles.
I聮m not completely dogmatic on this point, and chances are, if I were making this trip, I聮d pack in some cotton T-shirts and maybe even a few pairs of cotton underwear. I don聮t dispute cotton聮s comfort in hot weather; I just think it has limitations, especially for long-term wear.
Otherwise, I聮m sure you know the drill: Keep your head protected, drink plenty of liquids, and try to avoid hiking during the hottest part of the day. You聮ll actually adapt pretty well to the conditions if you don聮t rush things.
The votes are in: , including the year’s hottest backpacks, sunglasses, and digital cameras.