Parents hand out copies of the book at school board meetings. Administrators are relying on it for guidance on how to reduce the use of technology in their schools. Actor Hugh Grant promoted it and wrote a blurb for the cover. Practically overnight, Jared Cooney Horvath went from a relatively unknown educational consultant to the intellectual guide of a grassroots movement to limit screen time in schools, thanks to his self-published book “The Digital Delusion.” The book, which he released last