In the Innocence Cooper series, each book had at least one working title before getting its final title. Let's take a look...
Book #1, Confessions of Innocence:
First title: 'Darkness' - probably never a real contender for the actual title, but it was the name slapped on my early drafts.
Second title: 'Redefining Innocence' - yup, this one ultimately became book two's title, but it started life as an idea for book one. And yes, this is super-confusing if I ever want to look through old drafts.
Book #2, Redefining Innocence:
First title: 'Illuminating Shadow' - based on the idea that Innocence was going by 'Shadow' for a time.
Book #3, Trials of Innocence:
First title: 'Tears of Innocence' - if you've read it, I'm sure you understand. But it never really felt right, and 'Trials of Innocence' has a bit more meaning to the story.
Book #4, I Am Not Innocence:
First title: 'Queen of Witches' - I still love this one, but I really wanted this book to fit the pattern of the other titles and end with the word Innocence.