If the many books I have read on slavery in Rhode Island, they may have been the most verbose. The extent to which the author reiterates information is simply amazing. The most interesting parts of the book were the diagrams and the shopping logs.
The bible for study of the African Slave trade. RI led the American side of the slave trade. Rum to Africa for slaves sold in the West Indies for sugar to make RI rum. Almost 70% of the slave trade in America originated in RI. Coughtry's meticulous research documents 100 years of the RI trade. Unfortunately, the book is out of print and almost impossible to find. You can pick it up on Amazon for $200.
An enlightening history of the RI slave trade before and after the revolution. There is an interesting documentary, Traces of the Trade, by Katrina Brown also available in the library.