A free app for Android, by chepil.

It is the best way to have an organized and easy-to-use online collection of literature about the Jehovah’s Witnesses. It also makes it easy for you to navigate through the different sections of the online library. It is also very simple to use and will allow you to add personal study notes and even favorites. The tool is based on the data available on the website, so it is not an official application of the Watchtower Society and the data is not going to be downloaded and stored on your device. 

If you have an Internet connection, the tool will work smoothly.