The human brain can be seen as an immensely powerful, energy efficient, self-learning, self-repairing computer. If we could understand and mimic the way the brain works, we could revolutionize information technology, medicine and society. But to do so we have to bring together everything we know and everything we can learn about the inner workings of the brain's molecules, cells and circuits. The goal of the Human Brain Project (HBP) is to do this by integrating our knowledge in massive databases and in computer models of the brain. This will require breakthroughs in mathematics and software engineering and an international supercomputing facility more powerful than any before. This is all possible. Experimental and clinical data is accumulating exponentially. Computers powerful enough to meet the project's initial requirements are already here. An international team led by Europe's best neuroscientists, doctors, physicists, mathematicians, computer engineers and ethicists have assembled to begin the mission. As technology progresses and the project discovers new principles of brain design it will build ever more realistic models to probe ever deeper principles. The benefits for society will be huge, even before the HBP achieves its final goals. Models of the brain will revolutionize information technology, allowing us to design computers, robots, sensors, prosthetics and other devices far more powerful, more intelligent and more energy efficient than today. They will help us understand the root causes of brain diseases, and to diagnose them early, when they can still be treated. They will reduce reliance on animal testing and make it easier to develop new cures for brain disease. They will help us understand how the brain ages, and how to slow these changes and nurture a healthy brain for our children. In summary, the HBP is poised to produce dramatic advances in technology, a new understanding of the way the brain works and a new ability to cure its diseases.