Different people will, of course, find different aspects of abolitionism of interest. Personally, I find the theological issues of greatest interest, and in particular the paradoxical way in which the abolitionist movement brought together two extremes of the religious spectrums, atheists and evangelicals.
The atheists and evangelicals both were strong supports of abolition. The atheists argued from a secular perspective that all humans had inalienable rights by virtue of being human. Abolition was part of a general movement among radicals towards systems emphasizing human liberty as an end in itself.
Evangelicals were anti-slavery because they felt the system injured the souls of both slave and master. Their concern was less the outward condition if slaves than the freedom to work towards salvation.