True pioneers of the mind in any generation are a small minority. By pioneers we do not mean mere intellectual scouts who set out only to traverse new lands. Rather, true pioneers are both inventors and Schumpeterian innovators, people who both settle on and invest in new frontiers. But even among them there are divisions. Some are migrants like Daniel Boone (the legendary settler first of Kentucky and then of Missouri) of whom it was said that he 'moved on' as soon as he could see the smoke coming from a neighbour's chimney. However, some pioneers become permanent settlers, people who both open up virgin lands and cultivate them until they become fully-productive communities. There was more than a bit of both types in Harvey Leibenstein, whose productive career began as a graduate student: while writing (and publishing!) on the theory of demand, he developed a research programme for what later was recognised as experimental economics. From there he went to the research frontier of demographic economics, where he did pioneering work on the relationship between nutritional inputs and labour output as possibly the principal factor in economies overcoming the low-level equilibrium trap.1 Here in both cases he was more a pioneer of the first rather than the second type. Leibenstein's pioneering spirit of the second type shows up best in his work on X-efficiency analysis, where he both laid out a community blueprint and organized some early settling, with numerous articles, several books and doctoral dissertations. Unfortunately for that new community, already attracting immigrants from other productive areas, Leibenstein's career was cut short by an immobilising automobile accident in 1987 which left him nonproductive until his death in 1994. Thus, the economics profession and academia lost a leader, then at the very peak of his creativity. Such is our estimate, and in this essay we will try to put our case.