Hipolit Jamroz
Hipolit Jamroz voted up Anonymous' answer

If you count by commonly used labels then it's Christianity with Islam a close second and rapidly catching up.

However, considering that all Muslims follow the same one scripture, the HQ, whereas there are 84-book Eastern Orthodox Bibles, 81-book Ethiopian Bibles, 73-book Catholic Bibles and 66-book Protestant Bibles, if we count the number of followers of … Read more