Q: Is Tauriel in the Book, the Hobbit?
ANSWER: No. Tauriel is a character created by Peter Jackson specifically for his film adaptation of J.R.R. Tolkien’s The Hobbit, as are many other characters in both “The Lord of the Rings” and “The Hobbit” movies. It is a natural part of film adaptation to add, delete, or change characters. Fans of books that are made into movies often take exception with the character changes made by film-makers.
Introduced to audiences in “The Hobbit: The Desolation of Smaug”, Tauriel (her name means “forest maiden”) is presented as a native Silvan Elf who has risen high in the service and trust of Thranduil, king of the Wood-elves of northern Mirkwood. She appears (to me) to have the authority of a captain.
In an exchange between Thranduil and Tauriel in the movie, Thranduil implies that he will never allow Legolas to take a wife of Silvan Elf blood. This appears to be an acknowledgement of J.R.R. Tolkien’s various descriptions of Thranduil as a Sindarin elf (originally from Doriath in Beleriand) who in the Second Age migrated east with a few followers to establish a kingdom among the less sophisticated but more numerous Wood-elves.
In the book Unfinished Tales of Númenor and Middle-earth, Christopher Tolkien published some private essays his father had written which attempted to provide further detail about the kings of the Silvan Elves of Mirkwood and Lothlorien. In these private essays Thranduil turned out to be the son of Oropher, who was the original “adventurer” who established a kingdom among the Silvan Elves of southern Greenwood the Great.