Transcranial Doppler (TCD) ultrasound, first introduced more than a decade ago, has steadily evolved into a dynamic, reliable, reproducible, and practical diagnostic tool. Clinical neuroscientists have found TCD to be an indispensable technique in the management of many types of patients. This book is designed to provide basic instruction in the performance and interpretation of transcranial Doppler ultrasonography for technologists, nurses, and physicians. The information included in the text is critical for the development of a strong knowledge base. It is not intended to be all inclusive, and the TCD novice is likely to use it as the platform upon which to build his/her experience in the application of TCD. This book is organized as a step-guided approach for the performance of TCD, and it includes specific guidelines for interpretation of the TCD save forms. We hope that the reader finds it useful during what we think is the most difficult phase of this technique-the learning curve. John P. McCartney, R.V.T. Kathleen M. Thomas-Lukes, R.N., M.N.