First a few facts to get out of the way. This is not an original work by Tolkien, but rather his translation of three poems written in Middle English in the 13th century. The poems are all taken from the same Medieval document and are written in the same hand writing, but it is likely a copyist's handwriting and the poems likely all have different authors, but the authors' names are lost to history.
Sir Gawain and the Green Knight is an Arthurian adventure. The poem's style is alliterative, with multiple words in each sentence starting with the same letter. The effect is distracting and at times makes it challenging to follow the narrative as the reader gets a bit bogged down in the artificiality and oddness of the language. The story follows a knight of King Arthur's court who accepts a bizarre challenge to cut off a stranger's head and then one year later have his own head chopped off by the same man. It turns out to be an elaborate test of his knightly virtues, in turn testing his courage, honesty, generosity, chastity, and honor. I may reread this in a different translation as it is a fascinating narrative, but I feel I did not get everything out of it on a first read.
Pearl is a vision narrative in which a father mourns for his young daughter who has passed away. He is comforted by his Christian faith and has an elaborate vision in which he sees his daughter again in an afterlife inspired by the Book of Revelations.
Sir Orfeo was my favorite section of the book, although it is the shortest. Orfeo is a king whose wife is snatched away by the fairy folk. He abandons his kingdom to live in the woods and pursue his lost wife all the way to the other world of Faerie. The story seems to be an adaptation of the myth of Orpheus, with fairy land substituting for Hades. The ending also has elements of the homecoming of Odysseus from the Odyssey, with much less murder.
I decided to take a Christmas break from reading the very heavy Denial of Death by Ernest Becker, only to find that all of these stories are very much about death.