Question: Who is the writer of the bestselling book series Gone  and "Soldier Girls"?
Context: Barbara Tate (2 June 1927 – 12 November 2009) was a British artist and writer, perhaps best known for her bestselling book "West End Girls", which was published shortly after her death. The Almost Complete Collection of True Singapore Ghost Stories (also "True Singapore Ghost Stories" or "TSGS") is one of the bestselling book series in Singapore.  With over 1.5 million copies sold, the series has become a household name since its inception in 1989.  Russell Lee, a Singaporean author, compiles reports, stories and interviews about the supernatural.  Light and entertaining, each book, which comprises about 30 stories, appeals to both children and mature readers. Stephen McConnell "Steve" Case (born August 21, 1958) is an American entrepreneur, investor, and businessman best known as the co-founder and former chief executive officer and chairman of America Online (AOL).  Since his retirement as chairman of AOL Time Warner in 2003, he has gone on to invest in early and growth-stage startups through his Washington, D.C. based venture capital firm Revolution LLC.  Case authored "The Third Wave: An Entrepreneur's Vision of the Future" which became a New York Times bestselling book in 2016.  Case recently gave a fireside chat at TechCrunch Disrupt NYC, on May 16, 2017, titled "Building Silicon Valley Outside of the Valley." Front Lines is a young adult historical novel by the American writer Michael Grant, who is most famous for his dystopian young adult fictional series The Gone Series.  It is written from the viewpoint of three girls, Rio Richlin, Frangie Marr, and Rainy Schulterman.  The series was originally titled "Soldier Girls". Gone is a bestselling book series written by Michael Grant. GI Brides: The Wartime Girls Who Crossed the Atlantic for Love is a bestselling book by Duncan Barrett and Nuala Calvi, authors of "The Sugar Girls".  It was published by HarperCollins on 29 August 2013. The Spiderwick Chronicles is a 2008 American fantasy adventure film based on the bestselling book series of the same name by Holly Black and Tony DiTerlizzi.  It was directed by Mark Waters and stars Freddie Highmore, Sarah Bolger, Mary-Louise Parker, Martin Short, Nick Nolte, and Seth Rogen.  Set in the Spiderwick Estate in New England, it follows the adventures of Jared Grace and his family as they discover a field guide to faeries, battle goblins, mole trolls and other magical creatures. David Oliver Relin (December 12, 1962 – November 15, 2012) was an American journalist and the co-author of the New York Times bestselling book, "Three Cups of Tea", published in 2006.  Relin co-wrote the book with Greg Mortenson.  The book gives Mortenson's account of his transition from registered nurse and mountain-climber to humanitarian committed to reducing poverty and promoting education for girls in Pakistan and Afghanistan. Septimus Heap is the protagonist in the bestselling book series "Septimus Heap", by Angie Sage.  He is the Apprentice to the ExtraOrdinary Wizard, Marcia Overstrand.  He was once a member of the Young Army, known as Boy 412. Stones into Schools: Promoting Peace with Books, Not Bombs, in Afghanistan and Pakistan is a "New York Times" bestselling book by Greg Mortenson published by Viking in 2009.  The book is the sequel to the bestselling book "Three Cups of Tea" and tells the story of Mortenson's humanitarian efforts to build schools in Pakistan and Afghanistan with his non-profit charity organization, Central Asia Institute (CAI).  CAI reports that as of 2010, it has overseen the building over 171 schools in the two countries.  These schools reportedly provide education to over 64,000 children, including 54,000 girls, where few education opportunities existed before in the remote regions of Pakistan and Afghanistan.
Answer: Michael Grant