Atheism is discussed in many books. However none of these are regarded as "holy" as that would require a god(s) to inspire the book. Atheism has as its only principle that there is no god(s). Atheism does not have any of the other attributes of a religion such as beliefs other than the absence for a god(s)), secret handshake, meeting halls, tax exemptions, salvation, miracles, prophets, a hierarchy, leaders, traditional costumes etc.
It depends what you're agnostic about. If you're agnostic about Christianity then, in a sense, The Bible would be your holy book.
But really, being agnostic simply means you can see, and are willing to admit, that the existence of the gods can be neither proven nor disproven. The word is formed by "a-", meaning without, and "-gnostic", meaning knowledge. So an agnostic is simply one without knowledge of the gods existence. It is not a religion, but rather a stance, or opinion, about religion. You can be an atheist, or a member of a religion, and still be an agnostic. In fact everyone is an agnostic, whether they realize it or not, because the existence of gods obviously cannot be proven.
Of course, what most people mean when they say they're agnostic, is that they haven't really formed an opinion on whatever it is that they've declared they're agnostic about.
The Torah is the holy book of Judaism.
The religion is called Islam; the followers are called Muslims.
The Qur'an is the holy book of Islam, which is the religion followed by Muslims. It is believed to be the literal word of God as revealed to the Prophet Muhammad.
Freedom of religion is a right in France so there is no national religious book. The holy book would be of the religion of the person in question.
There is no such thing as the Jerusalem Holy Book. Jerusalem is a place, not a religion.
Guru Granth Sahib Jee is the holy book for the sikhs.
The Bible is the holy book for Christianity and it's many denominations.
Islam
Judaism, the Jewish religion.
I don't know what you mean but each Prophet has a book that came down upon them. That made the religions. For example; In the Islamic religion, the holy book is the Quran. In the Christian religion, their holy book is the Bible, while in the Jewish religion, their holy book is the Torah.
I don't think it is. From what I understand, "Sikh" refers to the religion, not specifically to their holy book.
Almost all major religions have holy books and holy languages.