Monocultures changed after the middle of the twentieth century. They grew in geographic size, technological complexity, capital intensity, and production volume, and they were increasingly impervious to control. Monocultures developed an unprecedented ruthlessness, but few things were actually new: a significant part of the transformation was about obstacles that fell by the wayside. After a long period of experimentation where many things were tried with varying degrees of determination and success, monocultures became unchained for better or worse.