R. Austin Freeman 
The Mystery of 31 New Inn [EPUB ebook] 

Second in the Dr. Thorndyke mystery series set in London around 1900. Thorndyke is a lawyer and medical doctor who reasons out mysteries. This involves a young doctor friend who Thorndyke hires as his assistant whose strange case involving a mysteries man and couple who are caring for him and an inheritance case brought to Thorndyke. A classic English mystery with the detective, Dr. Thorndyke, solving what appears to be two disparate mysteries. One is an apparent suicide with a disputed will; the other is one of his sidekick’s (Dr. Jervis) odd case of an apparent poisoning. Despite the twists and turns, the mysteries are solved.