Written in 1842 and addressed to "friends of the oppressed on the continent of Europe" (v) these eight letters set out to provide European abolitionists with facts and information in order to counter pro-slavery arguments. The letters address the subject of the slave trade and its abolition, slavery, apprenticeship, emancipation and the anti-slavery movement more broadly. Alexander also provides a bibliography of works published in English, French, Spanish, Portuguese and Dutch (vii - xiv), including pro- and anti-slavery tracts, official reports, and travel narratives, from which he cites at length in the letters. He suggests that the reader should take a critical approach to some of these texts: "the authorities quoted are of very different value", and that accounts of plantation life written by planters would appear very different from the viewpoint of their slaves: "Were the negro to describe facts, they would appear to be very different, and more conformable with truth" (xiii).