Much has happened in the field of superconducting radio frequency since the first book, "RF Superconducting for Accelerators", was published by Wiley in 1998. Radiofrequency superconductivity has become a major sub-field of accelerator science, and there has been an explosion in the number of accelerator applications and in the number of laboratories engaged in the field. In August of 2004, the International Technology Recommendation Panel recommended the superconducting option for the linear collider. This decision will further boost the development of the technology and will bring many newcomers to the field.