The title page for Ardency, presented above, alludes to the title page of A History of the Amistad Captives (1840) by John Warner Barber.
The full title for Barber's book was as follows: A History of the Amistad Captives: Being a Circumstantial Account of the Capture of the Spanish Schooner Amistad, by the Africans on Board; Their Voyage, and Capture Near Long Island, New York; with Biographical Sketches of Each of the Surviving Africans.
You can see Barber's title page here.
Like Barber's book, Ardency, too, was "compiled from authentic sources." Young's title page reflects an interest on the part of him and his publisher Knopf to further align this book of poetry with a historical work as well.
There is a small yet notable difference with the titles. Instead of presenting "biographical sketches of each of the surviving Africans," Young's book includes "phrenological studies of several of the surviving Africans." The mention of phrenology alludes to the inclusion of such studies in Barber's book and by others of the Mendi.
The reference to getting into the heads of the figures is also fitting, though, given Young's use of persona poems, where he must speculate and write about what James Covey, Cinqué, and the other figures were thinking.