If I hadn't read Mark Kurlansky's Cod, I wouldn't have known the vital role cod played in the settlement of North America. If not for cod, America might have never declared its independence. Cod was an important element in the facilitation of the slave trade. All news to me until I read Cod. (Well, until I read A Cod's Tale, which led me to read the full version.)
Cod reminds us that human beings are a connected part of our ecosystem. Too often, I think we perceive some sort of separation between us and so-called "nature." We are either concerned with or disregard our impact on the rest of the system, but we overlook how that system impacts on us. Mr. Kurlansky shows the human side of the equation. and how a lack of concern for the totality of our environment will eventually come back and bite us in the rear. We see how the reduction of the cod population has impacted on the world's fishing industry, and, more importantly, on the individuals who make up that industry.
Cod is an extremely well-done history book, detailed and easy to read. More importantly, it is clearly relevant to contemporary readers, demonstrating how the cycle of cause-and-effect continues to this day.