The phase diagrams of ternary systems of water/Aerosol-OT/ alkanol (having carbon numbers 5, 6, 7, 8, and 10) are presented. Appreciable single-phase zones with viscous regions at higher proportions of Aerosol-OT (AOT) have been witnessed for all the alkanols. The ternary systems have also shown water-induced percolation of conductance with multistep phenomena in some cases. The viscous preparations have behaved like Bingham liquids (the viscosity has increased with the rate of shear). The enthalpy of the solubilization of water in alkanol/AOT medium has been calorimetrically determined to be positive; the free energy has been evaluated from the knowledge of maximum water intake until phase separation. The free energy and entropy of water solubilization (derived from Gibbs’ equation) have been found to be positive and negative, respectively, and they follow a regular trend with the [alkanol]/[AOT] mole ratio (R) as well as with the alkanol carbon number. On the other hand, the enthalpy values, although they increased with R, increase with alkanol chainlength to a maximum for heptanol and then decrease for both octanol and decanol. It is considered that the heptanol acts as an efficient cosurfactant with AOT and helps to produce microdroplets with increased endothermicity.