This chapter provides a comprehensive overview of AlN single crystal preparation via PVT, tracing its evolution from early attempts in the nineteenth century to modern industrial-scale production. It emphasizes PVT as the dominant method, detailing its advantages over other techniques like HVPE and solution growth, particularly for large-diameter (>2-inch) substrates. The chapter explains PVT equipment configurations, including graphite and tungsten furnaces, highlighting crucible materials (e.g., TaC, W) and temperature control strategies (e.g., multizone heating). Key growth mechanisms are discussed, such as the thermodynamic growth window, N-polar orientation advantages for diameter expansion, and defect suppression through thermal field optimization. It also addresses seed crystal cultivation methods—heteroepitaxial growth on SiC substrates and spontaneous nucleation—and their impact on crystal quality. Challenges like optical transparency limitations and process scalability are addressed, alongside hybrid approaches combining PVT and HVPE. Finally, the recent breakthrough in 4-inch AlN substrate development by Crystal IS highlighted, underscoring PVT's role in advancing nitride-based optoelectronics and power devices.