This chapter considers the legalities of the posthuman embodied by Osamu Tezuka’s Astro Boy (鉄腕アトム: Tetsuwan Atomu, known in Japan by its original name, Mighty Atom).1 Through using the omnibus republished editions of Tezuka’s original manga from the 1950s and 1960s (which were published in English by Dark Horse Comics 2002-2004) it is shown that it is a text concerned with law. This is not, however, because many of the stories are ‘cops and robber’ crime stories or that some of the stories deal with discrimination against and the fights for civil rights, for robots. It is text about law in a fundamental sense in that throughout the diversity of the original manga there is a continual theme of transcending essence. Tezuka draws Atomu’s world as inhabited by beings that are constrained, yet struggle to overcome, their inherent limitations. Tetsuwan Atomu, in showing that essence does not limit nor constrain, shows good and bad are not determined by programming or by biology, but by choice and doing-in-the-world. In this Tezuka has drawn a world of responsibility, responsibility borne not so much from formal duty, but from participation in ‘life’. This could be understood as a techno-humanist law of love. However, instead of the latent paternalism that might attach to a serious ‘law of love’, what Tetsuwan Atomu reveals is a responsibility to ‘life’ that comes through engagement, play and laughter.