I love that one. I've read all of Niven's stuff and most of Pournelle's. Lucifer's Hammer and Footfall are in my top 5.
Of course, any of the Known Space stories/novels take the preceding 3 spots.
Thank-you for the suggestion of Footfall. There were just too many of Niven’s books to chose from ( and not in my library) that I just stopped. I just ordered it on Kindle. Please tell me what I should read of the Known Space books.