John Kendrick Bangs 
Toppleton’s Client [PDF ebook] 
Or, A Spirit in Exile

If you prefer your ghost stories to have a stout dose of rollicking wit, add Toppleton’s Client to your must-read list. A lawyer moves into a new office and soon discovers it is haunted — and worse yet, the lingering spirit wants to engage the lawyer’s services to oust another supernatural being that is squatting, so to speak, in his physical body.