Congo is an interesting Micheal Crichton novel, though it has a very slow start from the prologue to them arriving in Zaire. Not just slow, but, boring slow. It's very much an infodump about the technology and history. There's far too much emphasis on the history of exploration of the area of Africa where they are, and it's hard to tell what's real from historical accounts and what was made up by Crichton for the plot. 

There's something about Michael Crichton that hooks me every time. The characters and content feel so real, and the underlying issues raised stay with me after I've finished reading. In this book, the themes of technology outpacing humanity, animal intelligence and rights, and the cost of progress feel fresh and relevant, even forty years later. Plus, Amy is a star, and the most likeable character I've read in ages. Admittedly, some aspects haven't aged well (African tribal stereotypes around cannibalism, primitivism, etc.). Still, a thought provoking read that sticks with me.