The author discusses the art of improvisation in film making. This aspect of creativity is, he argues, one of the most neglected ones by the scholars. According to him the first improvisers in the history of the cinema were the brothers Lumiere, who filmed everything that happened in front of their cameras, whereas the first self-conscious improvisations were probably made by Feliks Kuczkowski, a long forgotten pioneer of Polish animated film. Unfortunately no trace of his work survives. The first surviving attempt of spontaneous cinema identified by he author is Man Ray's 'Return to Reason' (1923), who thanks to that particular film became one of the founding fathers of the whole genre of frameless film in experimental cinema, and a precursor of non-camera films. Non-camera films, especially the abstract ones, became one of the most responsive mediums for spontaneous cinema. The author considers work of this type made by Stan Brakhage and Norman McLaren, and he also mentions David Ehrlich and Jonas Mekas. The article is concluded by a manifest of spontaneous cinema, in which the author shows why spontaneous films are worth watching and filming.