Hi Richard,
you have the right title, the book you are talking about is Shadow of the Titanic, by Eva Hart & Ronald C. Denney.
you asked how good the book is and the answer depends on what you are looking for. if you are primarily looking for a book about the Titanic, this is not the book you want. but if you want to read about the life of a survivor, the book is very interesting.
Eva Hart discusses her experiences on the ship, of course, but then moves on to telling about the rest of her life, which has little to do with Titanic.
I would say that roughly a third of the book is Titanic related.
hope this helps,
Michael (TheManInBlack) T