Question: ’Twixt Twelve and Twenty is a book which offered advice to teenagers, by which American singer, composer, actor, writer, television personality, motivational speaker, and spokesman?
Context: Charles Eugene "Pat" Boone (born June 1, 1934) is an American singer, composer, actor, writer, television personality, motivational speaker, and spokesman.  He was a successful pop singer in the United States during the 1950s and early 1960s.  He sold more than 45 million records, had 38 top-40 hits, and appeared in more than 12 Hollywood films. Þorgrímur Þráinsson (born 8 January 1959 in Reykjavík), is a writer, motivational speaker and a former Icelandic footballer.  For the past twenty years, Thorgrimur has been Iceland’s most popular author of books for teenagers.  His writing has sold extremely well in Iceland, a country with a population of just 330,000.  Individually, his books have sold between 5,200 and 9,200 copies. Gregory Burns, MFA, (born 1957) is an American athlete, painter, author, motivational speaker and member of Art of the Olympians.  As a competitive swimmer, Burns represented the USA in the 1992, 1996, and 2000 Paralympic Games, winning five medals; he has broken five world records and numerous American records.  As a contemporary artist, his paintings have been shown in dozens of solo exhibitions plus dozens of group exhibitions in at least sixteen countries, and Burns has taught in thirty Artist-in-Residence programs around the globe.  He is the recipient of the United States Sports Academy’s 2016 Sport Artist of the Year award, (painter).  As an author, Burns has published three books in English and Mandarin.  As a motivational speaker, Burns has spoken to many audiences with a wide range of interests such as business, culture, and international relations. <ref name="Gregory Burns: Artist's Biography/Timeline"> </ref> Tinker Bell Talks: Tales of a Pixie Dusted Life is an autobiography by American actress, motivational speaker, radio host and author Margaret Kerry.  The memoir recounts the actress' lengthy Hollywood career, her faith and relationships through her life.  Starting in childhood appearing in "Our Gang" comedy shorts, being the reference model for the character of Tinker Bell in "Walt Disney's Peter Pan", her appearances on "The Lone Ranger" and "The Andy Griffith Show", and starring in "The Ruggles" on ABC-TV, to becoming a voiceover performer, a motivational speaker, and radio host.  The book includes 180 photos and artwork. David L. Bach is an American financial author, television personality, motivational speaker, entrepreneur and founder of FinishRich.com.  Bach, is best known for his "Finish Rich Book Series" and "Automatic Millionaire Series" of motivational financial books under the Finish Rich® Brand.  He has written 12 books since 1998 with over seven million copies in print.  Eleven of Bach’s books have been national bestsellers, including nine consecutive New York Times bestsellers, two of which were consecutive #1 "New York Times" bestsellers ("The Automatic Millionaire" and "Start Late, Finish Rich").  Bach has had four of his books "Smart Women Finish Rich, Smart Couples Finish Rich, The Automatic Millionaire and The Finish Rich Workbook" appear simultaneously on the "Wall Street Journal, BusinessWeek, and USA Today" bestseller lists.  Eleven of Bach’s books have been published from Random House (Broadway Books).  Bach's first book "Smart Women Finish Rich" was published in 1998, and appeared on the bestseller lists for a decade.  His most recent book "Debt Free For Life" (2011) was published by Crown Business Books, and appeared simultaneously on the "New York Times, "Wall Street Journal" and "USA Today" bestseller lists. Jairek Robbins (born May 26, 1984) is an American performance coach and motivational speaker.  He is the son of American life coach, self-help author, and motivational speaker Tony Robbins. Leslie Calvin "Les" Brown (born February 17, 1945) is an American motivational speaker, author, radio DJ, former television host, and former politician.  As a politician, he is a former member of the Ohio House of Representatives.  As a motivational speaker, he uses the catch phrase "it's possible!"  and teaches people to follow their dreams as he learned to do.  He was the host of "The Les Brown Show". Greg White (born 1959 in Mullens, West Virginia) is an American basketball coach best known, as the head coach at Marshall University and assistant coach for the UCLA Bruins.  He is also a well known motivational speaker on the speakers circuit in both the university and business world.  He has spoken to major corporations such as Mercedes, BMW, Subway, State Farm, Chevrolet, AT&T, Timken and Nisource to name a few.  On the college speakers circuit he has spoken at University of Alabama, Ohio State University, University of Kentucky, UCLA, Kansas State University, University of South Carolina, University of Louisville, Wake Forest University, University of Tennessee, University of Maryland, Iowa State University, Catholic University of America and University of Denver to name a few.  He graduated from the (now closed) Mullens High School in Mullens, WV and went on to play at NCAA Division I Marshall University, where he is a member of the school's Hall of Fame.  He was a record setting point guard, starting 113 consecutive games from 1977-81 and still holds numerous records at Marshall.  His legendary ball handling skills are world famous as he has traveled the globe performing as motivational speaker, exhibitionist and clinician.  His 115 wins as Marshall's head coach rank him as the 3rd winningest coach in Marshall Basketball history (29 coaches).  His teams amazed a 87-17 home record in Marshall's Cam Henderson Center.  Additionally, his teams at Marshall had a record setting 27 game home win streak and were 34-3 in home games against non conference teams beating foes like Wake Forest University, University of Georgia, University of Detroit and The University of Massachusetts.  In 2002, Greg's Marshall team lead all Division I basketball teams in 3 point field goal shooting percentage at 44% and he had 18 all conference players during his time as Marshall's head coach.  He had one player, Keith Veney, who hit 15 3's in a game which still stands as an NCAA record.  He has written several books with his most popular book being "The Winning Edge", a book about the importance of goal setting and time management.  In 2016, he published "Success: Attitude is Everything," a book focused on having a great attitude and strong mindset.  His basketball camps are the largest sports camps in the history of West Virginia at Marshall University and the University of Charleston attracting over 1000 per summer at their peak. Abiola Abrams (born July 29, 1976) is an American TV host, Internet personality, personal coach, motivational speaker and author.  Her advice columns on topics such as relationships and self-worth include "Intimacy Intervention" on Essence.com and "Abiola’s Love Class" on MommyNoire.com.  She is the author of the self-esteem advice guide "The Official Bombshell Handbook: The 13 Sacred Secrets of Feminine Power" and "Dare", a love story retelling of "Faust" set in the hip hop world.  Abrams is also the creator of a lifestyle blog and web video series at AbiolaTV.com. ’Twixt Twelve and Twenty is a book by Pat Boone which offered advice to teenagers.
Answer: Charles Eugene "Pat" Boone