This course provides a basic introduction to field balancing from first principles. Unbalance is one of the most common causes of machinery vibration. Nowadays vibration monitoring and analysis instruments typically include a dynamic balancing facility. These balancing programs can usually be relied upon for good results. Occasionally, however, things do not appear to go as they should, and it is useful in such circumstances to have an understanding of the fundamentals of balancing in order to speedily arrive at a solution.