Marine Protected Areas are subject to conflicting uses. As such, decision making analysis with respect to their management should be made on a sound base. This book was devoted to introduce the reader to the concept of economics, how it is implemented to natural resources management and especially how it could be applied to MPAs.The important lessons that can be learned are summarized in the following points:1. Economic decision making is based on the notion of efficiency.The efficiency criteria depend on the costs and benefits of different alternatives.2. We learned that there are different types of market failures in MPAs: Externalities (negative and positive), public good provision and Common Property characteristic.3. Common Property resources result in over exploitation of fisheries efforts and some times may lead to extinction.4. Different market failures result in the wrong signaling of development vs. preservation.We saw that while in most cases there is no market value to MPAs, still there is a social value that should be taken into account in the decision making process.5.We explained how to use these benefit estimation techniques in the CBA process. 6.We devoted an entire chapter to the financial importance of managing a viable and sustainable MPA.Almost never has an MPA the privilege of being financed by the government. Usually it has to rely on its own sources of revenue generation. May this be justified or not, it is a fact.To deal with that fact, a sound management tool is building a management plan and financial plan for any proposed MPA.In this book, we tried to raise questions rather than answering them. It is our hope that the readers can find the questions interesting and find the relevant answers in the references we have provided and in implementing the tools suggested to their own case study. Exercising the method suggested in the book might benefit the decision-making process of managing these important assets of the Oceans we all depend on as a society.