**1. Introduction**

Fetal surgery or in utero therapy tries to prevents or corrects multiple congenital anomalies in the fetus to prevent their severe consequences on later fetal development. It started with open fetal surgery then innovations toward minimally invasive procedures have occurred. In this chapter, we discuss the basic principles of fetal surgery, the general history of its development, important specific conditions and procedures used to treat them, and the future of the field.
