The heart of Suvin's book is a 110-page bibliography of science fiction published in Britain between 1848 and 1900, which is definitely its most useful feature; I have consulted his descriptions many times now, skimming for topics of interest (for example, violent uprisings) in order to direct my current research toward books of use.

The rest of the book is sort of a hodgepodge of essays on various topics, like "Nineteenth-Century SF and the Book Trade" (this one by John Sutherland), "Biographical Sketches of S-F Writers, 1848-1900," "The Social Addressees of Victorian Fiction," and "Narrative Logic, Ideological Domination, and the Range of SF." Some of them are better than others; Suvin is at his best when discussing transformations and influences of genres (I liked his categories of the different subgenres of science fiction pre- and post-1871, for example), and at his weakest when he gets too theoretical, or goes off on historical flights of fancy, or starts delivering value judgments based on his personal definition of science fiction, not one rooted in the period under discussion. So for some essays, I took lots of notes because there was lots worth nothing, whereas in other, I found nothing worth noting at all.