Monolayers of straight chain and 2-methyl branched chain alcohols with alkyl chain lengths of C-10-C-18 are experimentally studied by a conventional film balance technique combined with a Brewster angle microscope (BAM). The comparison of the surface pressure (pi)-area (A) isotherms with the corresponding BAM images provides information on the phase behavior and the first-order main phase transition of the monolayers. Striking differences in the dependence of the phase transition pressure on temperature of the straight chain and 2-methyl-substituted alcohols are correlated with differences in the molecular ordering. The general conditions for the main phase transition in the corresponding homologous alcohols can be derived. The effect of alkyl chain length and 2-methyl substitution on the general textural features of the condensed phase domains is determined under equilibrium and nonequilibrium conditions. n-Alcohol monolayers form defined and well-shaped condensed phase domains, often with inner texture in equilibrium. The long-range orientational order is strongly reduced in the condensed phase of 2-methyl-alcohols. Therefore, in the two-phase coexistence region of 2-methyl-alcohol monolayers only irregularly shaped domains without any inner structure are formed, which cannot be observed at the medium alkyl chain length C-14 because of the low contrast. Model calculations of the two-dimensional lattice structure of the racemic 2-methyl-hexadecanol on the basis of the pg space group are performed and correspond well with the reduced ordering concluded from the experiments.