How did Africa fall into the snares of the Atlantic slave trade? It is not that orthodox accounts suggest that slavery started one morning on January 1 in some distant and untraceable past, but they rarely trace the deep causes or brush them in favor of a simplistic narrative that frames abolitionism in terms of a gift from well-meaning Europeans.

Toby Green’s A Fistful of Shells is a solid attempt to grapple with the critique of political economy that led among other histories to the Atlantic slave trade and its dialectal opposite, the revolutions that brought down the nefarious institution (not Anglo-American abolitionism) by the end of the eighteenth century and the beginning of the nineteenth. Most enslaving African polities eventually fell into colonialism and the postcolonial present bears a lot of enduring traces, if not resemblances, with slavery times.

Green’s book is a game-changer. To support its claims, the author starts from the start: the late thirteenth and beginning of the fourteenth centuries, that is well before the geographical explorations and the Portuguese’ search for an alternative way to break the Ottomans’ monopoly over inland trade with India and the Far East.

Readers find that the central argument for Africa’s vulnerability to multiple forms of predations, not only trade in captives, is a particularly long one. Beginning from the fourteenth century onward, African polities such as the Mali and Songhay empires were known for swapping considerable quantities of gold in return for less formidable commodities such as cloths and iron bars or second-rate currencies such as cowries/shells. Given the present-day trust in gold as a standard of value, Green specifies that nearly all those who traded with Africans or came into contact with them eventually ‘cheated’ them out of gold. When the Portuguese appeared on West and Central-West African shores by the beginning of the fifteenth century, they simply wanted to outdo the Ottomans and Arabs’ access to gold for services and royalties with African caravans.

In seeking access to sub-Saharan Africa, we read that Arabs, Ottomans, and Europeans wanted to put their hands on the source of the most esteemed of metals. And when their supply of gold was exhausted, African kingdoms and statelets had to export human captives to maintain the same lifestyle they used to enjoy when gold had been in abundance.

Similarly, we read how revolutions erupted because of enslaving Africans. Exactly as the heads of Charles I of England and Louis XVI rolled in consequence of bloody reversals of fortunes in Europe, several African states and aristocracies such as Sokoto, Benin, and Oyo empires have been wiped off the face of the map. Still, the damage has been already done and the revolutionary orders that emerged from the slaving economies by the end of the eighteenth and early nineteenth centuries find the rules of global trade bypassing them. The rapid proliferation of credit decided the remaining African polities’ fate at the end of the nineteenth century through colonialism.

Green’s thesis is this ambitious because the claim for non-Africans’ predation on Africans highlights an undue trust in the finance economy. Finance ushered in complex credit networks from Lisbon and later from London. History would have taken a different course had these economies remained faithful to barter exchanges.

The book lies in eleven chapters stretching between two parts, titled “Causes” and “Consequences” respectively. Five chapters make the first part and six in the second. The fact that causality shapes a historical approach covering long stretches recalls the Hegelian method: intensity, measure, as well as the quantity that metamorphoses to quantity. The method saves readers from the stupidity of dubious accounts of slavery; those which note only what is visible, overlooking subterranean dynamics at play in the long run. For when engaging with A Fistful of Shells, the reader will dispense with simplistic accounts of mismanagement, distrust of authority, endemic corruption, or embezzlement that afflict most African polities today. Only when registering centuries of betrayals and enslavement, the reader will make sense of present scourges.

Trusting in Green’s thesis implicates that medieval Africans were at the heart of global trade. They simply did not wait for colonialism in the late nineteenth century to be introduced to history. Indeed, Africa’s gold and the value enslaved labor generated had been accelerators for complex international networks of trade that made the rise of capitalism possible. We find that the Ottomans could not seize Constantinople in 1453 and Cairo in 1517 without an eye on those West African caravans bringing in huge reserves of gold. Green’s referencing of states, kingdoms, and empires as markers of civilization taint the radical method of the book for states, as the evidence collected in the volume suggests, are enslaving structures by default, not by accident.

In this connection, access to rent money be it cowries, bundles of cloth, iron bars or gold spells a descent into slavery, an undue trust in the relative surplus-value. Contrary to commonsensical perception, money is never a neutral unit of measurement and exchange. Through its commodifying capacity, Karl Marx specifies that no one, no matter how powerful he or she is, owns money. It is money that owns and eats people. Therefore, it becomes a methodological glitch to claim that Africans were cheated out of solid currencies such as gold. The exchange value as an organizing principle hides not only the commodification of exchanges but also the commodification of human beings, hence falling into the snares of the slave trade.

Readers find in Green’s valuable account that by the time the supply of gold became exhausted, kings and princes not only had no qualms selling their own people, but these state structures become solipsist and psycho-frenetic entities. Green claims with little evidence though that all African exchanges studied in the book were never bartering economies. It becomes evident that because the sum of human labor determines the equality of exchange these economies become vulnerable. It could not have been the case with barter economies. For any quantity of labor to be measured and deemed equal, one cannot do without the abstraction of that which characterizes commodities, their quality. Slowly and unconsciously, the reign of quantity takes over quality—a course, once taken, automizes enslavement since both humans and human labor become valued only when quantifiable.

Still, it is worth recalling that even when cowries and cloth rolls or even iron bars were standardized as a means for exchange, Africans as early as the fourteenth and fifteenth centuries (during the Mali or Songhay empires) were nevertheless not yet fully subscribed in the commodifying principle as understood a little later (ever since the sixteenth century). We find that cowries were employed more as gifts (tokens of gratitude, love, and cherished memories outside the commodifying principle) for simple everyday necessities or in rituals. Hence, the reason why the thesis Green pushes regarding Africans’ modernity or readiness for globalization before contact with Arabia or Europe leads nowhere.

Meanwhile, the thesis which he does not articulate but whose masterful presentation thrusts nevertheless, that of the revolutionary movements that propagated towards the abolition of the slaving aristocracies, is not only interesting but radically subverts static perceptions of Africans as peoples living outside space and time. The fact these Africans like other peoples are endowed with logos (reasoning and acting capacity) to undo the contradiction from their enslaved status has to be underlined. That radical logos unleashed the dialectical interplay that specifies the historical necessity of reversing the valorization of their de-valorization as commodities, as slaves.

Now long-distance trade explains Africans’ fall from the plentitude, their alienation from the primordial order, and how slowly they become participants in the commodification of space and time. Access to credit spells the anticipation of future surplus value but that future surplus-value is quantified in the present thanks to the possibility of credit. Hence, the cheating of time by cashing on its mere chronological passage/passing. That explains why long-distance trade cannot indicate only Africans’ access to modernity! Long-distance trade underlines the transition from a fixed surplus value to a relative surplus-value, a situation that slowly but surely led to the crystallization of the necessity of revolution to resolve the contradiction. Unheeded in Green’s valuable account is how whether in mainland Africa, American plantations, or the Islands in between, enslaved Africans objected to their forced commodification, a disaster precipitated by long-distance trade.