The most comprehensive account of the story of Arthur, the Round Table and the Grail is to be found in the work known as Lancelot-Grail or the Vulgate Cycle. It tells the story of the Arthurian world from the events of the Crucifixion, where the Grail originated, to the death of Lancelot after the destruction of the Round Table. It draws in many different strands, from the pseudo-historical stories about Arthur to the romances of chivalric adventure and the spiritual quest for the Grail. It consists of five works: the longest is Lancelot, a kind of chivalric history of the Round Table, which leads into the quest for the Grail and Arthur's death. The first two books were added later, and provide an account of events through Arthur's marriage and early military victories. Not long after the cycle was completed, another writer retained the first two books of the Vulgate Cycle but recast the last three books with a rather different emphasis; this version is known as the Post-Vulgate Cycle, and is one of the main sources used by Sir Thomas Malory. The Quest for the Holy Grail adds a spiritual dimension to the adventures of Arthur's knights. Galahad replaces Lancelot as the central figure, though he appears and disappears so often that many of the knights are engaged in a quest to find him rather than the Grail.

The central concept of the Grail was never accepted by the Church, and the Quest remains a secular romance which can be interpreted as a spiritual allegory. This is done by the hermits who appear throughout the story, pointing out the meaning of each adventure. The adventures have a strong element of the magical and otherworldly, and the story is more closely structured than Lancelot, with the accomplishment of the Grail adventure by Galahad, Perceval and Bors as its centre and culmination. Book jacket.