This review is from: Heart of Darkness (Norton Critical Editions) (Paperback)
I am reviewing the Norton Critical Edition (revised 2006 edition), which, as well as containing Conrad's novella, has over 400 pages of supplementary material which is of great interest, and adds immeasurably to one's appreciation of HoD. Reading the other reviews, I see some people see this as a totally anti-imperialist work. I suggest these people need to read the supplementary materials to understand the deep ambiguities of the text. Particularly, the famous Nigerian writer Chinua Achebe published an essay in the 70s on racism in HoD that has been widely influential and is reprinted here (it's also freely available online). Conrad is obviously very critical of methods used by the Belgian rulers in the Congo, but whether he was ideologically opposed to imperialism is much more doubtful, as careful reading of HoD makes obvious.
The supplementary materials are in two sections: first is Background and Contexts. This includes Conrad's own letters and writings from his time in central Africa, extracts from Roger Casement's (an acquaintance of Conrad) Congo Report and other materials on the Belgian regime in the Congo and extracts from 19th-century thinkers on race, Hegel, Darwin, etc., among other stuff. The second section is Criticism, starting from contemporaries like Henry James and E.M. Forster, then later stuff including Achebe, postcolonialist critic Edward Said, and many others. There's even two essays on the film Apocalypse Now, loosely based on HoD, (in the 2006 edition, not in earlier editions), though these aren't, in my opinion among the best in the collection, and one on HoD in modern culture that references The Simpsons among other things.
Whether one likes it or not, HoD has been massively debated and by reading this contextual materials you get a great insight into key 20th-century intellectual debates on race, imperialism, civilization, the nature of mankind, etc. Therefore anyone who likes to think about big socio-cultural issues needs to understand the HoD debate, and this edition is a great way to do it.