Much of what we know about the Pilgrims come from William Bradford's writings. Most of the Pilgrims and their immediate descendants were simple, uneducated people who were unconcerned about the importance of the colony they founded. They did not even bother to keep town records in Plymouth until 1632. Early on in their settlement, they wrote and published to tracts trying to attract additional settlers. It is known as Mourt's Relation and makes an interesting read. I've included the link www.histarch.uiuc.edu/plymouth/mourt1.html. It was written by Pilgrims Winslow and Bradford, with Bradford's contribution largely being in the first section.
From 1630 to 1650, Bradford set about writing the history of the the sect and Plymouth, he describes the effort as "scribled Writings", "peeced up at times of leesure afterwards. During most of this time he was the Governor of the Plymouth Colony. He eventually titled his efforts "Of Plimouth Plantation" and it covered the story of the Pilgrims for 1606 to 1647. An electronic edition of his writings can be found at www.mith2umd.edu/ and makes interesting reading.
Bradford's manuscript was not published. For two hundred years, it was handed down from father to son. Occasionally, passages were copied into Church records by his nephew Nathanial Morton who as Secretary of the Old Colony used it as the basis of his own account of the colony in "New England's Memorial" published in 1669. Many years later, Bradford's manuscript turned up in the hands of Rev. Thomas Prince's library in the Old South Church in Boston where it remained until looted by the British during the American Revolution. Most disappeared until 1855 when it was discovered in the library of Fulham Palace, the residence of the Bishops of London, on the city's outskirts. The bishop allowed Bradford's writing to be published the next year.