Can I Stop App Maker From Using My eBook Title?

Dear Rich: I recently discovered that a new Apple app is using my exact common law trademark -- a phrase associated with my former profession. Through Apple, I contacted the app designer, who said she registered the trademark with the USPTO and it was tough luck for me. Since February 2013, I have used my trademark for the title of my copyrighted eBook, which is available globally on Apple, Amazon, Barnes and Noble, Kobo and Smashwords. Since that date, any cursory internet search for those keywords would reveal my eBook, my website and my personal contact information. How can I regain control of my common law trademark? I used the trademark first, the app trademark is identical, both are used for digital products and both are available in the Apple store (and appear in close proximity in online searches).
Sorry to deliver the bad news but if you've only used the phrase in connection with a single book title, you probably have not acquired any common law trademark rights. As the USPTO puts it, "the title of a single book cannot serve as a source identifier," and as we've indicated previously, only a book title used as part of a series is registrable as a trademark. There may be exceptions for blockbuster books but you would be in a better position to chase the app developer if you offered other goods or services with the phrase.
The app developer's trademark registration. Looking at the USPTO trademark records, it appears as if the app developer's statement that she registered the trademark may not be completely accurate. Although the examiner has approved the mark, there seem to be two steps remaining in the registration process: (1) publication of the mark on the Principal Register (which is supposed to occur on July 7, 2015); and (2) the app developer must submit evidence that the mark is being used in commerce (the developer filed an intent to use or "1B" application). That leaves two possibilities. First, you can file a notice of opposition following publication. We don't think you have sufficient basis to do that but you would be best served by seeking out a trademark attorney for guidance. Alternatively, the registration may not be granted if the app developer fails to file a Statement of Use  (or seek an extension) within six months of the Notice of Allowance (The USPTO explains these procedures.)
Copyright claims? If the app developer is taking more than the title from your eBook, you may be able to frame the dispute as copyright infringement.