This is a unique book in that it brings together the two key investigative techniques in Gynaecology and Obstetrics, namely ultrasound and endoscopy. So often in the past they were regarded by their exponents as rival techniques but it is now recognised that they are complementary to each other. Consequently future trainees in endoscopy should become efficient in transvaginal sonography and vice versa. Ultrasound can be used to study the morphology of the pelvic organs such as the endometrium, myometrium and ovaries, and being non-invasive, safe and convenient can be repeated as often as is deemed necessary to monitor changes over time; for example in the investigation of the infertile woman the development of the dominant follicle, the maturation of the endometrium and the formation of the corpus luteum can be documented throughout the menstrual cycle while growth of ovarian cysts can be precisely measured to determine the need for surgery. A seldom-mentioned strength of the ultrasound examination is its interactive quality, for example by performing abdominal palpation during the scan, the mobility of the uterus and ovaries can be assessed. Also the images as they appear can be shown to the patient to aid understanding. Ultrasound can also determine function and the use of Doppler has been used for example to access endometrial receptivity, follicular maturity and the likelihood of malignancy in the endometrium or ovary.