This is Christie at her best - it's the finest example of her work that I've ever read, and it's set the bar high for the rest of her bibliography. Hercule Poirot investigates a murder as he floats elegantly down the Nile, in a setting which has always fascinated me.
Christie's writing in Death On the Nile is gripping and fast-paced, and as the case develops you'll find yourself trying to detect who the murderer is yourself, although I'm not going to spoil it for you by revealing that here. Rest assured, it's highly recommended and worth reading whether you're a lifelong Christie fan or a newcomer to her works. There's certainly nowhere better to start.
Interestingly enough, Christie also makes references to her other novels throughout the plot, mainly during conversations between characters - they'd reference a mutual acquaintance in London for example, who'd also happen to be a leading character in a previous story. Something to spot for Poirot connoisseurs.
Published in 1937, this was released at a time when Christie was writing at her best, and you can feel the real sense of mastery that pervades the best of her fiction. Not many other Christie books can come even close, with the possible exception of And Then There Were None.
In summary, most Christie lovers will have read Death On the Nile already, but if you haven't then you should make it a priority. If you haven't read an Agatha Christie book before, then do yourself a favour and make a start on it, with this one. You won't regret it.