Is there a book of all these theories? I'd like to understand and memorize them.
Try these free courses about economics and finance.
http://alison.com/course/category.php?id=2
From my understanding, economics is about governing resources. Resources are used to make goods and provide services. For example, oil is used to fuel cars. Unfortunately, in western economics, some of these resources are limited and need time to be renewed. Since the demand of these resources is high and there is not enough resources to meet this demand, the distribution of resources must be governed. This is where supply and demand must be considered. Supply consists of goods and services. Where there is a high demand for goods and services, the price goes up since there is not enough supply to meet this demand. The opposite occurs where there is too much supply, so the price decreases to increase the demand, which increases profit and removes storage costs. Interest rates are to be considered here too. When interest rates are raised, it is supposed to deter spending and encourage saving (interest gained on savings account). Again, the opposite occurs when interest rates are lowered, so spending is encouraged in order to create jobs.
So you will learn about resources, supply and demand, inflation, interest rates, interpreting data (high mathematical content), recession and so on...
Learning about consumers is important but from what I have understood, supply and demand seems to be the core aspect of economics.
Economics is a lot more complicated but I hope I provided a simple introduction. I'm no expert but I have been reading articles on economics until I decided a degree in mathematics would be more suitable. It's a really interesting subject, go for it.