Andrew Loomis was one of the greatest illustrators of the 20th century, he wrote what could only be considered as bibles on how to draw the human figure. He was also a professor at The American Academy of Art in Chicago, Illinois. One of the finest art schools in the USA and probably the world and Alex Ross' alma mater.
This is where it begins, this is where Alex learned to draw such magnificent pieces. This is one of his greatest influences.
CLICK HERE to download some samples of Andrew Loomis' art books. Thanks to Alex Hays for posting this and to Jeremy Engel for sending me the link.