Don't Stop Readin'

This book was the adaptation of a play Agatha Christie had written and you could just tell by the writing that it was a very lanky one.
There was no mystery or anything of that kind at all. It was so clearly mentioned that Raynor slipped the tablet in Sir Claud's coffee. Since that moment it became clear who killed him.
I expected something to object to this, or some other revelation to come forward, but nothing. I shouldn't have bothered to read till the end.

Charles Osbourne should not have written about slipping the pill in coffee, then at least there would have been some suspense.