With the advent of the Clean Air Act in 1970, the number of air pollution control equipment installations has increased at an accelerated pace. Although much has been written on attaining collection performance with the various control devices, a major void has occurred in the identification and transfer of information needed to help reduce maintenance costs and to prevent deterioration of collector perform- ance. Although design and selection information is presented, it is the primary inten- tion of this book to discuss operation and maintenance topics and explore many of the repetitive problems that have plagued users of air pollution control equipment. The existence of these problems may be related to the complexity of the process or to a lack of well-defined operation techniques, among other reasons. In any event, this book intends to emphasize where and how these factors can have a major impact on the maintenance problems of control devices. Operation and maintenance problems have plagued users for nearly 100 years.