The purpose of this article is to review and analyze the degree of involvement and forms of F.E.Kaplan’s participation in the attempt on V.I.Lenin in a number of contexts, and above all in the context of the attitude to terror in the Socialist-Revolutionary Party. As a result of the research, the author comes to the conclusion that, as a member of the PSR, F.E.Kaplan, from the spring of 1918, appealed to the prominent leaders of the PSR with the proposal to commit an attempt on Lenin, but making sure that it was impossible to obtain permission for a party act (with the right to declare the act committed on behalf of the party and call herself a member of the party while being interrogated), committed an individual act (with withdrawal from the party and on her own behalf and under her responsibility), to which she received permission from a member of the Central Committee of the PSR and a member of the Moscow Bureau of the Central Committee of the PSR, D.D. Donskoy, who entrusted G.I.Semenov to assist her (and Semenov used this fact in order to go beyond the permitted), and that it was Kaplan who shot at Lenin. The official version that the attempt was committed with the sanction of PSR Central Committee by “Central combat flying unit” headed by G.I.Semenov is not true.