Francis Moore served as clerk and later factor with the Royal African Company in the Gambia between 1730 and 1735. The Company was integral in the intensification of the Atlantic slave trade from its establishment in 1660 under the patronage of James, Duke of York (later James II) to its decline in the mid-eighteenth century. It was responsible for the transportation of more enslaved Africans to the Americas than any other trading company. 

While in Gambia, Moore maintained a journal and after his return to London, published this account of his travels in 1738. It was the second account of the Gambia to be published in English, the first being Richard Jobson's The Golden Trade (1623, RCIN 1075287). While Jobson's book is notable for his abhorrence at the idea of purchasing enslaved people, it is apparent from Moore's text that he had no such qualms.

Compiled from his journals and his reports back to the factor at Fort St James (the Company fort from which enslaved people were transported), the work includes a detailed first-hand account of how the Royal African Company carried out the slave trade. Throughout the book, Moore details his own advocacy for the slave trade and his quest for greater profit, one passage describes his hopes that a market be established at Fort St James 'that is to say, if the Company kept a Stock of Slaves at the Fort, sufficient to furnish any Ship immediately with a whole Cargo, which as soon as disposed of they might again be supplied from their Out-Factories [factories established further up the river]. The separate Trader would afford to give a larger price at James Fort, than he can up the River...'. The policy of establishing markets in forts effectively gave the Company a monopoly on the trade and led to far more enslaved people being shipped from Africa than ever before.

Extracts from Moore’s descriptions of the slave trade, which often make difficult reading, were later used by abolitionists such as Thomas Clarkson (1760-1846) to support their cause. By the time the trade was abolished in the early nineteenth century, over 3 million enslaved Africans had been taken to the Americas aboard British ships.

Beyond its descriptions of the slave trade, the book also provides much important information on the Senegambia region before its colonisation. It describes Company installations, conflicts with French enslavers and the natural history of the River Gambia. The text also describes the culture and society of the Fula and Mandinka peoples, particularly the Fula kingdoms that had emerged following the collapse of the Mandinka-dominated Mali Empire the previous century.