The Ivy Tree Mass Market Paperback – November 12, 1987 by Mary Stewart
 
A trick of coloring...Her walk...The way she smiled. If Mary Grey looked so much like the missing heiress, why should she not be an heiress? To the lonely young woman living in a dreary furnished room, faced with an uncertain future, the impersonation offered intriguing possibilities.

And so plain Mary Grey became the glamorous Annabel Winslow. But she did not live happily ever after. In fact, she almost did not live at all. Because someone wanted Annabel missing...permanently.
 
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