A century of technology development and materials engineering has provided us with deposition processes for nearly every imaginable material. Interactions between process parameters and materials properties are generally well understood. Today, this allows the controlled deposition and crafting of complicated devices of which thin-ness and small-ness is a fundamental attribute. As the technology of thin films progressed from optical to electronic applications, the definition of 'thin' moved from the 100 nm scale into the <10 nm domain where atomic scale effects start to become important design considerations. The opening of the 21st century brings us to a convergence of thin film deposition with atomic scale engineering. Atomic layer deposition is aimed at nanoscale process control. Self-assembled monolayers provide surfaces with unique and useful properties. Microelectronic mechanical sensors require a broad spectrum of nanoscale engineered materials all based on thin film techniques. Approaching device applications from the opposite direction of the thickness scale, will challenge the thin film technologist to develop new methods to control the process and achieve practicality. The shift from inorganic to organic electronic materials is predicted to continue with concomitant changes in process technology. With microelectronics now reaching fundamental limits of miniaturization, thin film technologists will be forced to return to their beginnings, optical device technology, be it this time on a scale and with a required degree of control that was unthinkable in the last century.