Book excerpt: As an instructor in various finishing courses, I have frequently made the statement over the years that "In the field of metal finishing there is very little black and white, just a great deal of grey. It is the purpose of the instructor to familiarize the student with the beacons that will guide him through this fog. " To a very considerable extent, a handbook such as this serves a similar purpose. It is also subject to similar limitations. Providing all the required information would result in a multi-volume encyclopedia rather than a usable handbook. In the pages that follow, you will therefore find frequent references to other sources where more detailed explanations or information can be found. The present goal is proper guidance and the provision ofthe most frequently required facts, not everything that is available. In the 13 years since the last edition, changes in the finishing industry have been profound but in one sense have resulted in simplifying matters rather than complicating them. Because technology has advanced to a level of complexity rendering "home brew" impracti cal in many cases, dependence on proprietary compounds has become common. Therefore, detailed solution compositions are often no longer significant or even practical. It is thus more important to provide instruction about the factors that affect the choice of the most suitable type of proprietary material.