The influence of binaries on the evolution of globular clusters is studied numerically using the Monte Carlo method. It is assumed that initially the stellar systems are composed of single stars only and binaries are born /as a result of three-body encounters/ during the evolution of the clusters. The life of each hard binary in the cluster is studied individually. It is shown that the first binaries appear long before core collapse is completed, and then a population of a few hard binaries remains in the cluster during its whole life. Practically all energetic binary-single star interactions take place in the deep, internal parts of the core, populated mostly by the heaviest stars of the cluster. The binary-single star interactions become a source of energy which stops the collapse of the core and causes expansion and gradual disintegration of the whole cluster during the post-collapse phase.