"To lovers of the occult, 'The Flight of the Shadow...' will appeal with fine fascination.  It is a well-written argument for the astral world - a phrase which the theosophists are fond of employing.  A gallant young [Confederate] officer is stricken almost unto death.  In his delirium he is confronted by the spirit of a young man of his own age dead many years before.  The latter tells his story which is strikingly like the events of the former's life and weaves through it the arguments of occultism.  A note of love and mystery runs through the pages and makes of the volume a most charming one even aside from the queer theories it advances or supports."

The short novel, in part, takes place on a plantation in Charleston and is steeped in the Southern culture of the time, including slave dialect.  

The above review also gives clues as to the author's identity, she being a resident of San Diego, formerly of Columbia, MO, and wife of a Charles T. Dake.  OCLC lists Dake as the author of a religious novel, In the Crucible, and an anti-Mormon novel, which would make some sense given her upbringing in Missouri, called A Man O' Wax, published in San Francisco, 1902.  

Interestingly, an audiobook of this title was recently released.  Otherwise, we identify just the copy at the Library of Congress.   A true rarity of the genre.  

Not in Bleiler, not in Locke, not in BAL.  The New Sabin 9317.