This paper starts by outlining the technologies involved in RFIDs and reviews the issues raised by their general application. It then identifies their potential application areas within the library sector based on a generic process view of library activities. Finally it highlights the issues that are raised by their application in libraries and provides an assessment of which of these issues are likely to raise ethical concerns for library professionals. The purpose is to provide an overview of the technology within the context of the library process and to highlight issues which may raise ethical concerns for the profession. A second paper will focus specifically on these concerns within the context of the professional obligations of the librarian.