In order to understand how the components are combined to build a computer, you need to know Boolean algebra. There are many approaches to learning about Boolean algebra. Some authors start with the postulates of Boolean algebra and develop the mathematical tools needed for working with switching circuits from them. We will take the more pragmatic approach of starting with the basic properties of Boolean algebra and then exploring the properties of the algebra. For a more theoretical approach, including discussions of more general Boolean algebra concepts, search the internet, or take a look at books like Computer Systems, Digital Design: From Gates to Intelligent Machines, Digital Design, Third Edition, or Introduction to Logic Design, Second Edition.