Do the disbelievers include People of the Book?

In the Holy Qur'an, two categories of people are addressed in various verses: *the believers* and *the disbelievers*. Do the disbelievers include People of the Book, e.g. Christians and Jews? Here is an example: > Sahih International But if you do not - and you will never be able to - then fear the Fire, whose fuel is men and stones, prepared for the disbelievers.