I am attaching a copy of the chapter "Deductive Systems" from the book. This is a very readable and the concepts of consistency and completeness, introduced in section 6.4, are important. You may skip section 6.5.

Now that you have (hopefully) seen the definitions of consistency and completeness, I am attaching a short and nice proof of the fact that the nineteen rules that we discussed (rules of inferences+rules of replacement) are incomplete.