This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
A reader who sits down with two different janam-sakhi manuscripts expecting the same story of Guru Nanak's life will find something closer to two different lives. The broad shape survives across them, birth in the Punjab, a spiritual awakening, years of travel and teaching, but the episodes that fill that shape, which miracles are told, which encounters with rulers and holy men are included, even the order events occur in, shift from one manuscript tradition to the next. Scholars now group the surviving witnesses into several distinct lines, most prominently the Puratan, the Bala, the Miharban and the B-40, and W.H. McLeod's study was the work that first laid out this classification carefully enough for later research to build on.
That plurality is not a defect to be resolved by finding the one true version. Each tradition arose within a different community of Guru Nanak's followers, compiling stories that carried meaning and instruction for that community's own devotional life, and the differences between them are themselves evidence of how quickly and how variously his memory was taken up after his death. A genre with no single author was always going to look like this.
What the janam-sakhis are not is scripture in the way the Guru Granth Sahib is scripture. They sit alongside the Sikh canon as devotional biography, read and retold for the example and instruction of Guru Nanak's life, while the compiled hymns of the Guru Granth Sahib remain the tradition's one settled scriptural text.