Krugman, who is popularly known for his recent New York Times op-eds castigating both Bush and Obama, which are collected in several books of his,The Return of Depression Economics and the Crisis of 2008, Peddling Prosperity: Economic Sense and Nonsense in an Age of Diminished Expectations, The Conscience of a Liberal is a Nobel Prize-winning economist, noted for his work in international trade. His colleagues claim that his structural intuitions and proofs are beautiful.
Krugman says that he worked harder on this book than any other book that he wrote, making last-minute corrections and additions during his trip to receive the Nobel Prize. He made an effort to make every definition and explanation as lucid as possible.
A valuable feature of this book is that he and his partner/ co-author decided to include a section on the business cycle, while most other books available (prior to the recent credit crunch) eliminated discussion of the business cycle, thinking it to be eliminated by clever government fine-tuning of the economy. Once the book appeared, in the midst of the credit-collapse, this section became extremely relevant.
This is the most lucid and up-to-date introductory economics text presently available.