Read Human action from Ludwig von Mises. PDF: http://mises.org/books/humanaction.pdf Edit: http://mises.org has additional material like a study guide too.
Warning: this book contains the views of a small group of economists that the vast majority of the field would disagree with. See, e.g., awful austrians
I would like to learn more about economics but I don't know where to start. Can lesswrong suggest specific areas of economics that are particularly useful for understanding and optimising the world? Specific suggestions such as reading lists and resources would also be much appreciated.