I am a big believer that school isn't how we become well versed in something, it is a hunger for learning and a desire to constantly challenge and enrich ourselves. I have included the names of the books that have helped me to grow and expand as well as a link to where you can buy them secondhand on Amazon (I know, they aren't the best)... so I suggest first getting books at a local library, then purchasing books secondhand or on an e-reader if you have one. If you buy books secondhand online, remember to ask the seller if they can package it plastic free in an envelope as opposed to a plastic mailer. They are typically very accommodating.
The book that started it all for me:
Silent Spring by Rachel Carson: The book that was published in a series of 3 excerpts in the New Yorker in 1962 that led to the banning of DDT and helped to start the environmental movement.
Omnivores Dilemma by Michael Pollan: Through the question of what to have for dinner, Pollan looks at our food system and how America eats.
In Defense of Food by Michael Pollan: This book looks at the American Paradox- the more we worry about nutrition, the less healthy we seem to become. He suggest a "new" diet that looks in the direction of making thoughtful food choices.
Fast Food Nation by Eric Schlosser: A look into the American fast food industry.
Diet for a Small Planet by Frances Moore Lappé: a look into not only how what we eat affects us, but the world.
Flammable by Javier Auyero and Debora Alejandra Swistun: The impact of a large oil corporation on an Argentine shantytown.
Small is Beautiful: Economics as if People Mattered by E.F. Schumacher: A statement against "bigger is better" industrialism.
Cradle to Cradle by Michael Braungart and William McDonough: Remaking the Way We Make Things.
Guns, Germs, and Steel by Jared Diamond: Geography shapes the destiny of the world.
Natural Capitalism by Paul Hawkens: how businesses can be both profitable and environmentally responsible.
Collapse by Jared Diamond: How and why societies fail.
The Story of Stuff by Annie Leonard: The impact of overconsumption on the environment, economy, and our health.
The End of Poverty by Jeffrey Sachs
Enjoy these books and please let me know if you have any additions that I might have missed!