Fairy beliefs are mainly based on folklore. They mostly look like humans, subject to minor variations (insect-style frail wings, ability to transform into animals or plants). Stories about their origins range from fallen spirits to dead beings, ancient gods or “elementals” — mythological beings. The last comes closest to the Indian parallel of Yaksha who are also believed to nature-spirits, not always friendly.
Traditionally, fairies are mischievous and malicious. Mysterious illnesses and kitchen fiascos used to be written off as fairy work. Scottish folklore classifies the fairy-world into two. The Seelie Court being more benevolent (still dangerous) while the Unseelie Court comprising the wicked lot. Melissa Marr expanded on this division in her Wicked Lovely series (2007).
On the other hand, Aprilynne Pike in her Spells series makes fairies more elemental. They are half-human half-plant and are classified by the type of flower they bloom into. The division gets more hierarchical as the series unfold.
Since the early tales of legendary monarchs (Arthurian legends or a much later Spencer’s Faerie Queen) to Shakespeare’s A Midsummer Night’s Dream, Alexander Pope’s The Rape of the Lock, C.S. Lewis’ Narnia books or J.M. Barrie’s Peter Pan, the fairy feature has prevailed.
In the last decade however, the occasional appearance of fairies in literature was transformed into a robust genre with a range of fairy characters: The Artemis Fowl series by Eoin Colfer is a prime example. The same year also saw The Southern Vampire Mysteries by Charlaine Harris. Popularly known as the The Sookie Stackhouse Novels, it sees supernatural beings as real. The central character Sookie herself is a part-fairy. The fairy-world trend thus set early in the decade hit a home run with the readers.
There are seven novels so far in the Artemis series with a film on way, while Sookie ran into its 10th novel and third TV season in 2010.