Your book title - what's in a name?

Like most readers one of the key factors in capturing my interest is the book cover and the book title. Often as I'm sitting around a title will spring to mind and from that a story starts to develop. With current technology looking up books is easy. Yesterday the title "Darkest Hour" came to me. Immediately a story started to develop, but I wondered if there were other books out there titled Darkest Hour.

Amazon's database gives me instant access to researching titles so I went there and found that yes, there were actually several books with the title Darkest Hour.
This piqued my curiosity so I looked up my own books. With the exception of the addition of A Jacody Ives Mystery there were several books titled The Gifts and several titled or using the words Sacred Secrets in their title. I was a little disappointed. Not in my titles but in the fact that I had failed to do this research prior to naming my novels.

From there my curiosity led me to other research of famous authors and their book titles. I found that many of them had also used titles that were common in the book field and used by several other authors. All except one. Stephen King. I actually found that Mr. King had more unique titles than all the other authors I researched.
Why is this important? It may not be a matter of major importance. In fact, picking a book with a similar title may actually direct readers to your book when they're looking for one by another author. That could lead to sales. The piggyback effect.

For me though it was a matter of importance. I don't really want to piggyback on someone else's success. I want to develop my own. A unique set of books with unique titles and unique readers. With the vast amount of books being published daily is that possible? I doubt it, but with the vast databases at my fingertips I will definitely try to pick unique titles in the future. I can't guarantee that someone won't publish a book after mine with the same title, but hopefully I can assure that mine is the first. That too may be a difficult task as the book title depends on the book.

Is your book title unique?