The Silent History is not your typical science fiction e-book. It's a serial narrative from Eli Horowitz and Russell Quinn that uses geocaching to add to the story line. The ability to discover additional information about the plot from clues in your local environment sets The Silent History apart from other e-books and makes it incredibly interesting.
The e-book tells the story of children who are born silent, but possess powerful skills. It's narrated via daily updates called testimonials. Each update gives you a glimpse into the characters as the story unfolds over the course of a year. Besides testimonials, the e-book also includes field reports, which can only be read in specific geographic locations.
These field reports can be found in alleys, buildings and include other small items in our surroundings. One reviewer describes finding a field report when she passed by a name carved into a cement sidewalk. The first wave of field reports were created by the makers of the book, and they have invited fans to contribute their own narration for the the next round of field reports.
The Silent History is available for free from the iOS App Store, but you will need to purchase the volumes in order to read the book. You can buy all the volumes (1-6) for US$8.99 or try out the e-book by purchasing just volume 1 for $1.99. If you decide you like it, you can then buy volumes 2-6 for $7.99.