The growth, characterization, and electrical properties of ferroelectric and piezoelectric single crystals will be the focus of my talk. In Part I, after a brief introduction of crystals and growth of artificial crystals, the crystalline structure of single crystals and their characterization will be presented. In addition, the origin of ferroelectric and piezoelectric behavior will be discussed and the relation of structure and property will be emphasized. Examples of applications of ferroelectric and piezoelectric single crystals will be shown. In Part II, I will introduce my research on the ferroelectric and piezoelectric single crystals Ba(Zr,Ti)O₃. By adopting the Laser Heated Pedestal Growth Technique (LHPG), I have grown Ba(Zr,Ti)O₃ single crystals, whose high quality has been confirmed by Laue pattern, four-circle X-ray single crystal diffraction, X-ray powder diffraction, and electrical property measurements. The polarization hysteresis of BaTiO₃ crystals is greatly suppressed by partially substituting Zr for Ti. This makes the material a good candidate for many applications. In Part III, I will report our research on Cd₂Nb₂O₇ ferroelectric/ferroelastic single crystals. Its unusual dielectric response under dc electric field makes it a unique ferroelectric that has received much attention since the 1960s, but its physics is still unclear. Based on the "Landau-Ginzburg-Devonshire" phenomenological theory, we have proposed a "Multi-polarization-Mechanism" model, which can describe the observed behavior very well. Finally, a summary of these concepts is given.