Ferroelectric materials are used in a wide variety of applications, including multilayer ceramic capacitors, piezoelectric transducers, actuators, sensors, and energy harvesters, pyroelectrics, and electro-optic devices. This tutorial will discuss key applications of ferroelectric materials, and the structure-property relationships that govern the choice of specific materials. Emphasis will be placed on the use of modified BaTiO3 in multilayer ceramic capacitors, and perovskite ferroelectrics for piezoelectric applications, including both lead-based and lead-free piezoelectric ceramics, single crystals, and films.