The Giver Quartet is a series of four young adult novels by Lois Lowry.
 The quartet consists of "The Giver" (1993), "Gathering Blue" (2000), "Messenger" (2004) and "Son" (2012).
 The first book won the 1994 Newbery Medal and has sold more than 10 million copies.
 The story takes place in the world of the Giver.
 Each book has a different protagonist, but is set in the same futuristic era.
Katherine Womeldorf Paterson (born October 31, 1932) is a Chinese-born American writer best known for children's novels.
 For four different books published 1975-1980, she won two Newbery Medals and two National Book Awards.
 She is one of three people to win the two major international awards; for "lasting contribution to children's literature" she won the biennial Hans Christian Andersen Award for Writing in 1998 and for her career contribution to "children's and young adult literature in the broadest sense" she won the Astrid Lindgren Memorial Award from the Swedish Arts Council in 2006, the biggest monetary prize in children's literature.
 Also for her body of work she was awarded the NSK Neustadt Prize for Children's Literature in 2007 and the Laura Ingalls Wilder Medal from the American Library Association in 2013.
 She was the second U.S. National Ambassador for Young People's Literature, serving 2010 and 2011.
Joseph Quincy Krumgold (April 9, 1908 – July 10, 1980) was an American writer of books and screenplays.
 He was the first person to win two annual Newbery Medals for the most distinguished new American children's book.
Lois Lowry (born Lois Ann Hammersberg; March 20, 1937) is an American writer credited with more than thirty children's books.
 She has won two Newbery Medals, for "Number the Stars" in 1990 and "The Giver" in 1994.
 For her contribution as a children's writer, she was a finalist in 2000 and U.S. nominee again in 2004, as well as a finalist in 2016 for the biennial, international Hans Christian Andersen Award, the highest recognition available to creators of children's books.
 Her book "Gooney Bird Greene" won the 2002 Rhode Island Children's Book Award.
Messenger is a 2004 young adult fiction by author Lois Lowry.
 It forms the third installment of "The Giver Quartet" begun by her 1993 Newbery Medal-winning novel "The Giver".
 This novel takes place about eight years after the events of "The Giver", and about six years after the events of "Gathering Blue".
 Characters from the two earlier books reappear in "Messenger," connecting the novels more strongly.
 Set in an isolated community known simply as Village, this novel focuses upon a boy named Matty, who serves as message-bearer through the ominous Forest that surrounds the community.
Jean Edna Karl (July 29, 1927 in Chicago, Illinois – March 30, 2000 in Lancaster, Pennsylvania) was an American book editor who specialized in children's and science fiction titles.
 She founded and led the children's division and young adult and science fiction imprints at Atheneum Books, where she oversaw or edited books that won two Caldecott Medals and five Newbery Medals.
 One of the Newberys went to the new writer E. L. Konigsburg in 1968 for "From the Mixed-Up Files of Mrs. Basil E. Frankweiler".
Katrina Elizabeth "Kate" DiCamillo (born March 25, 1964) is an American writer of children's fiction for all reading levels, usually featuring animals.
 She is one of six people to win two Newbery Medals, recognizing her novels "The Tale of Despereaux" (2003) and "Flora and Ulysses" (2013).
 Her best-known books for young children are Mercy Watson series illustrated by Chris Van Dusen.
Gathering Blue is a young adult-social science novel, written by Lois Lowry and released in the year 2000.
 It is a companion book to "The Giver" (1993) being set in the same future time period and universe, treating some of the same themes, and is followed by "Messenger" (2004), and "Son" (2012) in "The Giver Quartet".
Elaine Lobl Konigsburg (February 10, 1930 – April 19, 2013) was an American writer and illustrator of children's books and young adult fiction.
 She is one of six writers to win two Newbery Medals, the venerable American Library Association award for the year's "most distinguished contribution to American children's literature."
Elizabeth George Speare (November 21, 1908 – November 15, 1994) was an American writer of children's books, best known for historical novels including two Newbery Medal winners.
 She has been called one of America's 100 most popular writers for children and some of her work has become mandatory reading in many schools throughout the nation.
 Indeed, because her books have sold so well she is also cited as one of the Educational Paperback Association's top 100 authors.

Question: Gathering Blue is a young adult-social science novel, written by which American writer credited with more than thirty children's books, and has won two Newbery Medals?
Answer: Lois Lowry