Hi,   this is my first post....  Atacama is my first 4 deserts event and i just wanted to share a few things that may helps newbies like myself.....   My running history is brief - i ran my one and only marathon 6 months ago and since then havce tried to build a solid base ahead of the Maclehose 100km that took place last weekend (of which several friends on here completed....)  As far as i am concerned the Maclehose was a success - although i did the event somewhat differently to everyone else.... firstly i broke it into 2 parts to try and simulate the 4 deserts a little better - it also meant i could run more than if i just tried to slog out 100km in one go.  Basically i wanted to see how my body reacted to consecutive days of time on feet....  What i did was 47km on friday,  44km on saturday and then another 20km on sunday - and i got through it unscathed - i was able to run most of the flats and downhill sections and the hills provided a good test for muscles and mixed terrain a good test for the shoes and soles of the feet !!   The reasons for its success (and here is where i hope it helps you guys...)  1.  my back-back was incredibly comfy (the OMM 25 litre - i have my doubts whether big enough but i hope so - still plenty of time to try slightly bigger but an excellent bag that fits tight to the back and also nicely around the stomach / on the hips.  2.  no blisters (wow!) -  vaseline on feet and injinji socks with another pair of ultra thin socks over the top (from RTP store) - i am amazed not even a hot spot as i was on my feet for approx 7hrs, 6hrs then 2hrs - i am also a 90kg + guy and not the most agile of creatures - i am definitely sticking to this strategy of double-socking + vase for Atacama....  3.  Montrail shoes very comfy (only half size too big - may go one size too big for Atacama but not sure yet as feet did not really swell - maclehose was cold i guess but with double-socking could maybe remove a pair if it gets tight during the event.....)  - the montrail where the grey and yellow ones (i am not yet an equipment geek ! )  I hope this is helpful to at least one person - very happy to swap training tips with people but i am a novice so others with experience can be more useful i suspect.  Anyway, nice to write something at last.... good luck to everyone with their training, all the best, John.