The volume runs to 1,430 pages in the standard printing, which is fixed, so that any line can be cited by page number and found in any copy anywhere in the world. It is arranged not by author or by subject but by raga, thirty-one of them, and within each raga by metre and then by Guru in order.
It contains the compositions of six of the ten Gurus, of fifteen Bhagats, of eleven Bhatts and of four others including Bhai Mardana Ji and Baba Sundar Ji. The Bhagats include Kabir Ji, Namdev Ji, Ravidas Ji, Sheikh Farid Ji, Trilochan Ji, Dhanna Ji, Sain Ji, Pipa Ji, Sadhna Ji, Bheekhan Ji, Surdas Ji, Parmanand Ji, Jaidev Ji, Beni Ji and Ramanand Ji. They were Hindu and Muslim, of many castes, and several were from outside Punjab entirely.
The languages in it include Punjabi, Braj, Sadhukkari, Persian, Sanskrit, Sindhi and Marathi, all written in Gurmukhi.
Guru Arjan Dev Ji compiled the first recension in 1604 at Amritsar, dictating to Bhai Gurdas Ji. Guru Gobind Singh Ji produced the final recension at Damdama Sahib, adding his father's hymns, and dictated it to Bhai Mani Singh Ji. He added none of his own.
In 1708 at Nanded he ended the succession of living Gurus and installed the volume as Guru. It is treated as a living Guru in practice, given a room, put to rest at night, and carried on the head.
The raga order is the structure and it is a musical decision before it is a doctrinal one. Every composition carries the raga it is to be sung in and usually the metre and the ghar as well. The volume was assembled to be performed and its arrangement is a performer's arrangement rather than a reader's.
Nothing in it is narrative and nothing in it is law. There is no account of the Gurus' lives, no ritual instruction, no code of conduct and no history in it at all. A scripture that contains no biography of its own founders is unusual enough to be worth saying out loud.
The standard printing dates from the twentieth century and the fixed pagination comes with it. Before that, handwritten birs varied in arrangement and in what they carried, which is why the manuscript question matters and why the older birs sitting in almirahs across Punjab are evidence and not only objects.
Guru Granth Sahib Ji, standard 1430-page printing.