Theoretical and experimental evidence is presented to demonstrate that the maximum stable growth rate of crystals growing from slowly cooled solutions must decrease as the crystal size increases and the solute concentration decreases. Temperature programs derived for a constant linear growth rate are therefore unlikely to result in the growth of high-quality crystals. A cooling program based on the theoretical maximum stable growth rate is calculated, and it is shown that a constant cooling rate should give stable growth except in the early stage following spontaneous nucleation. Practical procedures are suggested for the growth of large crystals of good quality by slow cooling of high-temperature solutions. © 1972.