Eugene Genovese has passed away. He was a historian of American slavery, and his views were not particularly popular or discussed in economics courses, as far as I know. Mainstream, quantitative historians suggested that his view that slavery in the South was not profitable was incorrect (in particular Engerman and Fogel, the latter a Bank of Sweden prize, also known as the Nobel, winner). The other reason, I imagine, that made his work particularly difficult for mainstream authors was his use of Marxist categories, including one that I still find essential for historical analysis, namely: the notion of mode of production.
Genevose (I read only his The Political Economy of Slavery and not the classic Roll, Jordan, Roll, often praised as his best work) argued that slavery was an economic drag to the Master class, and that the system remained a pre-capitalist formation, with the profit motive having a secondary role in the process of social reproduction. The idea was that, even if the South was connected by trade (cotton mostly) with the capitalist production in England (and New England too), the commercial relations where not central for the relations of production in the plantation system [I find his argument very unconvincing, by the way].
In other words, very much like Dobb, in the Transition debate with Sweezy, Genovese argued that the trade link was not central and could not define the South as part of the capitalist mode of production. In this sense, Southern slavery was for him a distinctive mode of production, one that was seen increasingly from a positive angle by Genovese, as he became more conservative and remained, interestingly, critical of the capitalist mode of production (which in a sense makes him more in tune with old conservatives that also repudiated the mercantilization of social relations).
Note that Genovese, like Engerman and Fogel in this case, thought that the peculiar institution was quite more benign that it is usually thought. In this sense, he reminds me of the quintessential Brazilian analysis of slavery in The Masters and the Slaves, by Gilberto Freyre, who also, even if for different theoretical reasons, saw Brazilian (not Southern, even if he saw similarities) slavery as benign and helped create the myth of Brazil as a racial democracy.
PS: On the slavery debates Nate Cline suggests this paper by Wallerstein (subscription required).