This chapter examines Slaughterhouse-Five (1969) through the lens of Niklas Luhmann’s systems theory. The novel’s unique power is a result of its unconventional form, which recapitulates its primary subject – the firebombing of Dresden – while simultaneously excluding it. Luhmann’s concept of autopoiesis, in which a system reproduces itself recursively from its own primary organising principle, and observation, in which systems become ‘aware’ of a given subject via exclusion, are used to explain the novel’s form. Its famously non-linear structure is also recursive, bootstrapped into being by an event that, by its nature, cannot be properly portrayed. Observational blindspots are also evinced by the novel’s characters, who, bound as their own autopoietic systems, are fundamentally incapable of understanding others except by reference to themselves; suffering is the only universal, and even then, it is totally incommensurate. Ultimately, the recursive, self-enclosed depiction of time and of existence itself in Slaughterhouse-Five is nevertheless founded on its unsaid, undepictable Other and thus on the kind of paradox Luhmann describes as ‘productive’. This is the defining feature of Vonnegut’s oeuvre: the impossibility and necessity of action in an absolutely determinate universe, through the paradoxical action of observation and of art itself.