The Commons are all of Nature and all of Culture. It is hard to know where to start or end on this huge a topic. You could spend your entire lifetime studying the Commons. And so you should, because the Commons are the realities that are the life of a human being on planet Earth.
A good place to start is Wikipedia, which is a commons in itself. This article gives a broad overview of history and current usage of the term Commons. There also many links to follow.
The Tapestry Project Essays has a list of articles we collected. You scroll down to read them all. The best overview is - Karen Coulter's "Rule of Property" which has an historical overview tracing roots of the commons and property. Mary Zepernick's article "Th Impact of Corporations on the Commons" discusses just that. And David Bollier's Article "Common Sense"is subtitled Community Ownership and the Displacement of Corporate Control. These 3 pieces are near the top and are open up the topic for the more specific articles to follow.
Friends of the Commons is a big website on the Commons. Be sure to check out the "State of the Commons Report". A good site to explore how big the concept of the Commons can be. However, the Tapestry of the Commons does not agree with their solution to Commons protection.
Reclaiming the Commons by David Bollier is a long article with historical background illustrating modern concerns. It starts with an excerpt from the following poem.