Here is another good book to read on your mobile.
Apostles of Denial: An Examination and Expose of the History, Doctrines and Claims of the Jehovah's Witnesses
by Edmond C. Gruss.
http://archive.org/details/ApostlesOfDenial
First published in 1970. This was Gruss' first work on Jehovah's Witnesses and he has subsequently authored three additional titles on the Witnesses. Permission for non-commercial distribution on the Internet granted by the author on January 22, 2009 provided no changes are made to the text. Book was originally written as a Master's Thesis and was subsequently enlarged and updated. This PDF version includes an additional chapter entitled: "Russell's Bible Student Movement -- A Millerite Offshoot" taken from "Jehovah's Witnesses: Their Claims, Doctrinal Changes, and Prophetic Speculation. What Does the Record Show?"