When you get to the authors' lucid explanation of the main ideas behind calculus, you'll realize that (1) calculus isn't scary, (2) the computations you need to learn how to do are fun, not hard, and (3) everything comes down to a few very intuitive ideas -- it may have taken geniuses like Newton and Leibnitz to come up with them in the first place, but they are part of our common intellectual heritage, not erudite ideas reserved for mathematicians and physicists.
And, although it's not a textbook, there are some exercises which will give you the chance to test your understanding. Again, though, they are fun, not grueling.
Now it's true that certain industries are natural monopolies (in the sense of economics: they require large capital investment in infrastructure, which results in high barriers to market entry and enables the sort of tactics other commenters have described, pricing competitors out of the market when they do crop up. Many of these industries seem to work better for society when they are government-regulated utilities, e.g. sewage, electricity, water, police and fire protection. But that doesn't mean that the government should be allowed to run any industry which is a natural monopology. In particular, I think it's best to maintain a healthy distrust of government when it comes to running media of communication which are necessary for political speech and dissent from government policies. Internet, phone, and cable services, I believe, fall into this category.
Another example might be newspapers, which are obviously about to go out of business, because website redistribute for free the content produced by the papers' journalists. Some people have proposed endowing newspapers as nonprofit organizations. Another possible model, I suppose, would be having the government pay journalists to do their reporting, which would then be delivered to citizens, e.g. online. But no one (I hope) would seriously consider this a good idea for "saving" journalism --- we would end up like with a state-controlled media of questionable objectivity, not really worth a damn.
The moral? Be wary when the government owns the flow of information. It's a Good Thing that the ISPs are being challenged. But hopefully private enterprises can accomplish the same thing, too.
At a lower level, Conway and Guy wrote an excellent book called "The Book of Numbers". It's got enough in it that a bright middle school or high school student could read it cover to cover four or five times and pick up something new and interesting on each read.
Another good book, written at an elementary level but sophisticated in content, is "Geometry and the Imagination" by Hilbert and Cohn-Vossen.