The chapter begins with a Link to the Tale of Tinúviel in which the current state of Eriol's stay is made clear and he tells shorter tales of where he comes from. The main lovestory about Tinúviel and Beren is told by Vëannë and since it features ~40 pages this post will be split in half. My commentary will be provided in the second post and this one contains half the plot and a few features to note.
The tale of this chapter concerns how Melko manipulated the Noldoli in order to get hold of the the precious gems that they had made and to create distrust towards the other gods. The chapter also features the theft of the Silmarils and the ruin of the Trees of Light.
In this chapter the tale is still told within the Eriol-framework, this time told by Meril-i-Turinqui. The text deals with limpë and the relation to long life and desires of elves and men as well as the relationship between the Valar and Melko.
This passage is basically the first part of the creation myth that Tolkien designed for the world he wrote about. It tells about how Ilúvatar sang the Ainur into being and how the world and elements became real. The story mainly deals with Ilúvatar's vision and design of the world - through music.
The first part of the chapter "The Music of the Ainur" consists of a text which picks up from where the "Cottage of Lost Play" ended. It mainly describes a meeting between Eriol and aged Rúmil who dwells at the cottage and cares for the garden. This part forms a link between the "Cottage of Lost Play" and the tale of "The Music of the Ainur".