New from the University of North Carolina Press: 
Freedom's Debt: The Royal African Company and the Politics of the Atlantic Slave Trade, 1672-1752 (Dec. 2013), by 
William A. Pettigrew (University of Kent). A description from the Press:
In the years following the Glorious Revolution, independent 
slave traders challenged the charter of the Royal African Company by 
asserting their natural rights as Britons to trade freely in enslaved 
Africans. In this comprehensive history of the rise and fall of
 the RAC, William A. Pettigrew grounds the transatlantic slave trade in 
politics, not economic forces, analyzing the ideological arguments of 
the RAC and its opponents in Parliament and in public debate. 
Ultimately, Pettigrew powerfully reasons that freedom became the 
rallying cry for those who wished to participate in the slave trade and 
therefore bolstered the expansion of the largest intercontinental forced
 migration in history. 
  Unlike previous histories of the RAC, 
Pettigrew's study pursues the Company's story beyond the trade’s 
complete deregulation in 1712 to its demise in 1752. Opening the trade 
led to its escalation, which provided a reliable supply of enslaved 
Africans to the mainland American colonies, thus playing a critical part
 in entrenching African slavery as the colonies' preferred solution to 
the American problem of labor supply. 
A blurb of note:
"With startling precision, Pettigrew reveals the role of liberal 
political and market institutions in bringing about the massive 
eighteenth-century acceleration of the British Atlantic slave trade. All
 of us must ponder this deeply researched account of how 'a 
distinctively British conception of freedom' drove the expansion of 
slavery." --Christopher Tomlins
More information is available 
here.