Scanning tunneling microscopy and "molecule corrals" were used to measure the temperature dependence of the rate of molecular ordering in monolayer liquid crystal films. Molecule corrals are circular etch pits, 3.35 Angstrom deep on the basal surface of graphite formed by high-temperature oxidation. A strong negative relationship between temperature and nucleation rate was observed, consistent with a nucleation growth mechanism of molecular self-assembly. From a fit of classical nucleation theory the melting temperature of the film was found to be T-melt = 318 +/- 6 K, the thermodynamic driving force for nucleation Delta F-n(T-melt - T)/T-melt = 1.1 +/- 0.3 kcal mol(-1), and the preexeponential factor A = (1.8 +/- 0.8) x 10(8) Angstrom(-2) s(-1).