I came in knowing nothing about Oracle except that it was a database program. I didn't even know exactly what to do with it. If you are in a similar situation, then this book is good, because it'll get you on your feet, and introduce you to what it's all about. It will give you a VERY LIGHT introduction to most features of Oracle.
However, once you need to do anything useful, this book SUCKS. I installed Oracle on my system, and I needed to somehow log in. How do I do it? What are the default passwords and accounts? This book did not tell me anything on this subject. In the examples for the installation procedure, they say "Let's assume you have an account Polly with the password 'gone'" HOW DID THEY CREATE THIS USER WITHOUT FIRST LOGGING IN???? HOW DID THEY LOG IN??? They never explain this, and these types of oversights are throughout the entire book.
Basically, if you know nothing about Oracle, this book explains things in a way that you can understand what the purpose of all the functions and programs are. If you want a 2-minute introduction to everything, get this book, and then once you roll up your sleeves, go buy another one. I don't regret buying this book, but I quickly realized I needed another one to help me do anything useful.