The Dream Cycle, also known as the Dream Quest Cycle, is a series of short stories and novels written by the American author H.P. Lovecraft between 1918 and 1932. These stories revolve around the "Dreamlands," a vast and mysterious dimension that can only be accessed through dreams.

One of the key elements of the Dreamlands is its geography, which is divided into four main regions. The West region features the seventy steps of deep sleep, the enchanted forest, the port of Dylath-Leen, the village of Ulthar where no man can kill a cat, the coastal jungle city of Hlanith, and the commercial capital of Ilarnek. The South region is home to the island of Oriab and the Fantastic Realms. The East region includes the city of Celephaïs, created by King Kuranes, and the dangerous Forbidden Lands. The North region is where the feared Plateau of Leng is located, inhabited by man-eating spiders and the Men of Leng. Other notable locations include the Underworld, the Moon inhabited by lunar beasts, and Kadath, a massive castle on a mountain ruled by the Great Ones, the gods of the Dreamlands.

The Dreamlands are ruled by a small group of deities known as the Great Ones, who reside in the citadel of Kadath and depend on the Outer Gods for protection. Lovecraft's Dream Cycle is intricately connected to the Cthulhu Mythos through various tales, such as "The Statement of Randolph Carter," which introduces the protagonist Randolph Carter and initiates a series of dream adventures.

Access to the Dreamlands can be physical, through tunnels inhabited by various monsters, or through dreaming. The Dreamlands are populated by a variety of mythological creatures, including gugs, spider of Leng, basilisks, moon-beasts, and many others. Lovecraft even created a detailed map of the Dreamlands, depicting the various regions and landmarks that make up this fantastical world.