There is no one answer for this, I think. This book is in "story within a story" format. The inner story is clearly first person, but you'll need to decide about the outer (or frame) story.
http://en.wikipedia.org/wiki/Heart_of_Darkness
http://www.google.com/search?q=point+of+view+in+literature&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a
What kind of narrator is used by Joseph Conrad in "Heart of Darkness"?
a.second person limited
b.first person limited
c.third person limited
d. third person omniscient
1 answer