In recent decades, the field of design has expanded. Moreover, there has been a significant historical shift to a world essentially defined by artifice. The onset of the Anthropocene - the epoch in which human impact upon our planet has become irreversible - is the most dramatic symptom of this phenomenon. In these conditions, we are forced to consider the extent to which design should be understood less as a subaltern moment of action, and more as a necessary mode of acting in general. But what then are the characteristics, the advantages, the limits, and the possibilities of understanding acting in general through the model or lens of design? In particular, is the model of "action as design" capable of engaging with the destructive tensions bequeathed to us by the industrial economy, now reinforced by neo-liberalism? This book offers a conception of our times, an examination in what is entailed in this view concerning the character of our century, and explores the implications of design and acting in the 21st century. Its underlying insight is the following: today it is the artificial, and no longer nature, which constitutes the horizon, medium and condition of existence.