Part I of the second of four volumes in Research Report No. 7 of the Health Services Mobility Study (HSMS), this book contains 76 task descriptions covering most of the medical activities carried out by radiologic technologists. Chapter I of this volume defines "tasks" and tells how the descriptions were developed. Chapter 2 lists the tasks by system or area of the body, by the type of task function involved (such as "plain film" examinations, contrast examinations, teaching), and by main type of recipient (e.g., patient, pediatric patient, etc.). The steps of the task descriptions are presented in logical sequence in considerable detail by Code Number in Chapter 3, (part of which is in this book, Part I, the remainder in Vol. 2, Part II). (The work carried out by diagnostic radiologists and the tasks of administrative, machine-related, and nursing-type functions are found in Volumes 1 and 3. Volume 4 is an index of all the tasks in the three volumes. These task descriptions are offered for use as instructional materials, design of career ladders, for the structuring of jobs, and as inputs to the development of performance evaluation instruments and proficiency tests). (HD)