dr. mark cucuzzella is quite a phenomenal individual, and i can't help but think that what born to run has done for the running community in print he has helped to do in spades for the same community via video.
i also came across this video (isn't YouTube great?) that is equally as helpful and instructional - but i found it after dr. mark's, so it falls to second in priority and preference:
as the post title indicates, these videos have made all the difference in the world to me - in terms of how efficiently i run, how long i plan to run injury-free, and the enjoyment that i can experience in running. watch at your own discretion - once you travel down the rabbit hole, there's no going back.