This is a technique of inner work described by Castaneda. Recapitulation involves making a list of all persons with whom one has interacted throughout one's life and remembering in vivid detail any places one has been to, situations one has experienced and so forth. This may involve traveling to places, keeping a journal of memories, written notes etc.
The idea of recapitulation is to free oneself from one's past through bringing it to consciousness. This is similar to the idea of modern psychotherapy but recapitulation is primarily to be done as a private exercise.
Recapitulation seeks to integrate all aspects of memory, a bit like self-remembering seeks to integrate all aspects of a present moment. The technique stimulates memory and associations and may offer interesting material for self-observation in the form of discovering surprising networks of apparently unrelated associations.
As with such techniques in general, effects are liable to vary greatly between individuals.