This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
You could learn it just well enough to use it in a simple project; or you could learn it well enough to use it in a complex project; or you could learn it well enough to write a book about it. So it depends what level of learning you are aiming for as well.