Interesting, well-formed characters carry the plot through some lulls in the beginning, but the pacing picks up as the novel progresses. A few conspicuous points date the novel, but overall its a quick and interesting read, the prototypical action/adventure that set the tone for the genre that emerged from it.

Malone, the young, lovesick narrator of the story, seeks a great adventure to win the heart of his beloved and advance his career as a journalist. His search for adventure leads him to the bombastic Professor Challenger, one of the most vivid and interesting characters in science fiction. In an effort to corroborate Challenger's claim of a lost prehistoric world hidden deep in the Amazon; Malone, Challenger, bold adventurer Lord Roxton, and contentious skeptic Professor Summerlee embark on an adventure into the unknown.

Like many novels of its period, many aspects are problematic when viewed through the lens of our current cultural sensibilities. Women seem to be largely absent from the novel, save Malone's object of desire--the motivator for the whole adventure--who is flighty and inconstant. The local Amazon guides ("Indians," "half-breeds" and the "faithful Negro") are given the expected treatment, and the warring red-skinned "savages" on the prehistoric plateau face supposedly equal opposition from the "ape-men," missing link figures that the expedition encounters. While it's important to maintain cultural relativity in understanding the period in which the book was written, a modern audience might find these points occasionally jarring.

Still, even if the cultural attitudes and scientific practices (and for that matter presumptions of how dinosaurs look and act) are questionable today, the vivid and timeless personalities written into the main characters make up for it. Each is, in his own way, larger than life such that they should all be unrelatable, but somehow it works in the context of this fantastic setting.

Once the action got going, I found it a hard book to put down.