The Grey Annals are the chronology made by J.R.R. Tolkien that comprises the first part of The War of the Jewels, which is the eleventh volume of The History of Middle-earth. They were the first large-scale timeline of Middle-earth, and their final version in Tolkien's legendarium is the Timeline of Arda.
"These are the Annals of Beleriand as they were made by the Sindar, the Grey Elves of Doriath and the Havens, and enlarged from the records and memories of the remnant of the Noldor of Nargothrond and Gondolin at the Mouths of Sirion, whence they were brought back into the West."This chapter of the book, or part, can be seen as a synopsis of the happenings of the first half of Quenta Silmarillion, which was written afterwards. The years by which the Annals were ordered are called "Valian Years", being named after the Valar. Interspersed throughout, and in the whole second half of the chapter, are Christopher Tolkien's notes and explanations of changes his father had made to people and locations, and of references made within the Annals to external, historic Middle-earth tales.
The Annals begin with the Valian year 1050, in which Melian the Maia came from Valinor and the Quendi were awoken in Cuiviénen - they end with the last events of The Children of Húrin; specifically the inscription of Túrin and Niënor's gravestone, which are in the year 499 of the First Age.
The Grey Annals, which are Part One of the book, are followed by "Of Men", the first section of Part Two.