Best tool to make digital interactive ebooks

To my knowledge, there are several tools, such as iBooks Author, Kotobee Author, and Ridero, that can facilitate the creation of interactive ebooks faster than using Storyline, as they are specifically designed for this purpose - potentially reducing the time it takes compared to how long it takes to create the app from scratch. These tools offer features like multimedia integration and easy publishing, and the exact timeline will depend on the size and complexity of the materials.