Who is Hercule Poirot from Curtain and what is their importance?

Hercule Poirot is the famous, French investigator responsible for solving some of the toughest cases in the country and even the world. He's an older gentlemen in his 70s. He is not married and doesn't have any children.

His health is failing. When the novel opens, Poirot is staying in a guesthouse ins Styles St. He has just returned from a trip to Egypt, where he saw a doctor about his heart problems. He is in a wheelchair and he has let his longtime caretaker, Georges go, and replaced him with a new caretaker, Curtiss.

Poirot's keen senses and attention to detail are what helps him to solve his murder cases, robberies, and other mysteries. Poirot invites his long time friend, Arthur Hastings, to Styles to solve five murder cases. He tells Hastings that he needs Hastings to take care of physical aspects of the investigation, as well as be his eyes and ears, because Poirot doesn't get around as well as he used to. Poirot doesn't come downstairs to dinner in the novel, but retires to his room prior to dinner starting.

Occasionally, Poirot has Curtiss push his wheelchair outside to take in the fresh air. During his life, Poirot has always been somewhat of a hypochondriac. Now that Poirot knows he's dying, he isn't so concerned with his health, but is really biding his time until his heart takes him, but hoping to solve the murder cases prior to going.