I recommend An Internet broadcast featuring Brian Doherty. He argues that libertarianism was so unfashionable in the 1940's and 1950's that the process of natural selection was bound to yield quirky individuals.
He sees the link between economics and libertarianism as coming from the fact that economists see how order can emerge without a planner. So, while a non-economist cannot imagine how we would have schools without government school boards, economists have relatively easy time visualizing how a market would work.
Unlike Bryan, I have not read the book. But I strongly recommend the interview.