I strongly recommend the original article. It meanders for a few hundred words before hitting its stride (Coase was English and born over a century ago) but it's a real masterpiece. Many of Coase's ideas were so simple as to seem a bit trite in summary, but develops them in interesting counter-intuitive ways, and from first principles rather than relying on mathematical truisms.

also, many of his talks are on Youtube; I regret not having had the opportunity to hear him speak in person before he died recently. Great thinker.