Knowledge is the great fifth production factor in our economy, besides capital, labour, land, and entrepreneurship. Perhaps it is the most precious of the five factors, because it takes so much effort and money to keep it well-nourished. Perhaps it is the most strategic of the five factors, because we depend on it to develop business, the economy, and the world at large in a balanced and sustainable direction. Knowledge is certainly one of the least understood factors and one of the hardest to grasp. This book concerns the largest pool of knowledge, which is professional knowledge. This form of knowledge, albeit being very close to business practice, is nonetheless least understood of all. Economists have tried to grasp the knowledge factor, measuring and assessing it in terms of the pools of R&D-expenditures, patented innovations, licences, and other forms of knowledge that can be documented. The pool of professional knowledge is not among these, because it is tacit. It can only exist in our head; it is intrinsically tied to people --the professionals. Professional knowledge is the articulation of scientific and documented knowledge, and the individual experience and dexterity of individuals. It is for this reason that it is so hard to grasp; while for this very same reason, it is so close to the life of business, to the shopfloor of our advanced economies.