In line with recent post-modern research, this text argues for a global change never before realized on such a scale. I refer to 21st century communism. Communism has not been defeated, only its relatively immature 20th century form. To cross from late capitalism to a sophisticated communism based upon the advances of the current conjuncture is a task for those who would live dangerously. Indeed, the waters of this crossing upon the river of time are deep. But the depth of a river is the imagination of those who dare cross it. The vessel of the crossing is theory.Without revolutionary theory,‘ said V.I. Lenin , there can be no revolutionary movement.’ However, the production of theory has a social context, namely, theactual life practises of a world belonging to a specific conjuncture. The world is undergoing constant change, and theory must both reflect upon and reflect that. Guided by Marx’s words and example, I have undertaken the task of fitting dialectics within contemporary scientific discoveries, beginning with chaos theory.A communism for the 21st century points to the possibility of order unfolding from disorder. According to this schema, it is necessary to hold both order and disorder as simultaneous realities while locating the dynamic of their operation vis-a-vis asubstrate. I tentatively identify this textual body as the confluence of several strands, blending relations between different but complimentary elements: dialectical method (Plato-Hegel-Marx); the striving for social justice (Hebrew prophets and Marx) and; science (specifically fractal logic, chaos theory, general systems theory, string theory).