Sort:  

Which Book do you claim didn't rely on preceding knowledge?

Thanks for stopping by dear Jimmy. Guru Nanak's Knowledge is not Bookish Knowledge, his knowledge is pure experience. There is two types of knowledge; one is attained by reading books or listening to others (this knowledge is very much same as we gather water in a tank using the hose). Second type of knowledge is attained by experience it got created inside you once you perform a certain task or routine (this knowledge is very much like water of a spring coming out itself by ripping apart Earth's crest).

Let's ask Guru Nanak Himself, what he says about his knowledge:

ਜੈਸੀ ਮੈ ਆਵੈ ਖਸਮ ਕੀ ਬਾਣੀ ਤੈਸੜਾ ਕਰੀ ਗਿਆਨੁ ਵੇ ਲਾਲੋ ॥
Jaisi mai avai kẖasam kī baṇī ṯaisṛā karī gi▫ān ve lālo.
As the Word of My Lord comes to me, so does it become my knowledge, O Lalo.

There are many other occasions Guru Nanak tells the source of his knowledge. Such as

ਅਪਰੰਪਰ ਪਾਰਬ੍ਰਹਮੁ ਪਰਮੇਸਰੁ ਨਾਨਕ ਗੁਰੁ ਮਿਲਿਆ ਸੋਈ ਜੀਉ ॥੫॥੧੧॥

Then we should explore ourself as done by Guru nanak and that will be his ultimate respect and then take Guru granth sahib or any other holy book as reference.

That's the purpose of life dear brother Jimmy. If each of us learn how to die while living then there will be no more pain and suffering at this planet.

:)