Murder of Roger Ackroyd by Agatha Christie

This is supposedly the best novel by Agatha Christie, and is third published to feature Hercule Poirot, although he is already retired in the plot. It is a well written book. It flows well and the language is clear and intriguing. I am not sure if the plot twist is so unexpected. I guessed the doctor and narrator was the murderer about 25 pages in. The best part about the book is the delves into the side-stories of all the characters and how each story becomes novel-worthy on its own, though subservient to the main plot in this book. 

The plot is that somebody murdered Roger Ackroyd, who is rich but miserly and very difficult with money, not giving her sister in law and her niece enough to cover their expenses, but wanting a justification for each spend.  Also he is quite stingy towards his own adopted son (as he never married), who is at his wits end and gets secretly married, though it is not explained why the son couldn't just find a proper employment that would allow him to pay his expenses by himself, without having to beg his step father. 

Roger Ackroyd is also tangentially guilty of the suicide of a woman who was in love with him and poisoned her abusive husband. Ackroyd could not get over the poisoning and the woman, while also being blackmailed, killed herself. There are other illustrious characters, each of whom with something to hide. At the end Poirot tells the doctor that he knows he committed the murder and advises him not to attempt to murder him (Poirot) as well, which is strange because that would be the logical thing to do for the doctor who is already a murderer.

Also Poirot tells Dr. Sheppard that he might choose to kill himself instead of surrendering to police the next morning, which is a very controversial suggestion (that the doctor actually acts upon). Even if he is a murderer he can have his time in court and be sentenced according to the law. The plot happens in 1920s England, which is unlikely to have had automatic death sentence for murderers at the time. Poirot says it is to spare the doctor's sister, Caroline, the embarrassment. Who cares about the embarrassment of some old spinster - a human life is worth much more than that.  Poirot also comes across as not-very-sympathetic person throughout the book, but the incitement to suicide at the end, because of some 'honour' preservation is completely bonkers.