Earlier Sunday, Engadget reported an inexplicable uptick in sales of book apps by a developer identified as Thuat Nguyen. According to the blog, at the time of writing its report, Nguyen apps accounted for 42 of the top 50 books by revenue in the Books section of the iTunes App Store. Engadget went on to mention "a number of people reporting up to hundreds of dollars being spent unwillingly from their [iTunes] account to these specific books."