Classicly

A Husband by Proxy is a detective and mystery novel set on Inheritance and succession written by Jack Steele.

Excerpts:

While he stood there a shadow fell upon the glass. Someone was standing outside, in the hall. As if undecided, the owner of the shadow oscillated for a moment—and disappeared. Garrison, tempted to open the door and gratify a natural curiosity, remained beside his desk. Mechanically his hand, which lay upon a book entitled "A Treatise on Poisons," closed the volume.

He was still watching the door. The shadow returned, the knob was revolved, and there, in the oaken frame, stood a tall young woman of extraordinary beauty, richly though quietly dressed, and swiftly changing color with excitement.