It features hymns by seven men, including its compilers Arjun and Gobind, but its most important hymn is the Japji, written by Nanak.  
The Akhand Path, requiring forty-eight hours of continuous reading of this book, is undertaken during each of the main gurpub festivals, and although the Khalsa Consensus translation of it is available online, the faithful are expected to learn Gurmukhi in order to read it in the original.  It features hymns by seven men, including its compilers Arjun and Gobind, but its most important hymn is the Japji, written by Nanak.  Accorded the status of a guru, FTP, what is this sacred book of Sikhism?
The Akhand Path, requiring forty-eight hours of continuous reading of this book, is undertaken during each of the main gurpub festivals, and although the Khalsa Consensus translation of it is available online, the faithful are expected to learn Gurmukhi in order to read it in the original.  
Adi Granth (or Sri Guru Granth Sahib)