The energetics and reaction paths of polymeric forms of fullerenes have been investigated by means of calorimetry experiment and semiempirical molecular orbital calculations. Energy schemes of three types of single phase C-60 polymers i.e., dimer, one- and two-dimensional polymers have been experimentally established. This energy scheme, as well as the dramatic difference in experimental conditions for the polymerization and the depolymerization, is reasonably explained by a calculated energy contour map taking the distortion of fullerene molecules into account.