normalization question

I am a database user who wants to become more knowledgeable. I purchased a book on SQL and it has a chapter on "The Relational Model". In this chapter the book briefly describes the process of normalization. I probably need a more general database book in addition to a book specifically about SQL. At any rate, I have read the section on normalization and I don't quite understand what it means.

What would be a good defination of normalization? Could someone explain what the first through third normal forms are?

If I can grasp the concept of normalization (especially first through third normal forms), then I think I will have overcome an obstacle to really grokking relational databases.

Of course, part of this process is going out and purchasing a better book but any info you can provide here would help get me started...

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Manatee Morton