I look at the general problem of "designing" properties in solids; about how one tries to go about selecting a crystalline structure type, and then the composition, in order to obtain a specific property. The properties I address relate to magnetism and polar behavior. The specific systems that I will talk about are insulating spinel magnets, and nonmagnetic pyrochlore oxides with a (frustrated?) tendency to polar ground states. Aspects of the preparation of bulk materials, structure determination, electronic structure calculations, and property measurement will be covered. I will also try and and address the question: Why perovskites ?