The Association of Tennis Professionals or ATP was formed in 1972 by Donald Dell, Jack Kramer, and Cliff Drysdale to protect the interests of male professional tennis players. Since 1990, the association has organized the worldwide tennis tour for men and linked the title of the tour with the organization's name. In 1990 the organization was called the ATP Tour, which was renamed in 2001 as just ATP and the tour being called ATP Tour. In 2009 the name was changed again and is now known as the ATP World Tour. It is an evolution of the tour competitions previously known as Grand Prix tennis tournaments and World Championship Tennis (WCT). The ATP's Executive Offices are in London, United Kingdom. ATP Americas is based in Ponte Vedra Beach, United States; ATP Europe is headquartered in Monaco; and ATP International, which covers Africa, Asia and Australasia, is based in Sydney, Australia.

The counterpart organization in the women's professional game is the Women's Tennis Association.

Started in 1972 by Jack Kramer, Donald Dell, and Cliff Drysdale. It was first managed by Jack Kramer, as Executive Director, and Cliff Drysdale, as President. Jack Kramer created the professional players' rankings system, which started the following year and continues to this day. From 1974 to 1989, the men's circuit was administered by a sub-committee called the Men's Tennis Council. It was made up of representatives of the International Tennis Federation (ITF), the ATP, and tournament directors from around the world.

Novak Djokovic (Serbian: Новак Ђоковић or Novak Đoković; pronounced [nɔ̂ʋaːk dʑɔ̂ːkɔʋitɕ] ( listen); born 22 May 1987) is a Serbian professional tennis player who has been ranked World No. 1 by the Association of Tennis Professionals (ATP) since 4 July 2011. He has won five Grand Slam singles titles: the 2008, 2011 and 2012 Australian Open, the 2011 Wimbledon Championships, and the 2011 US Open. By winning three Majors in 2011, Djokovic became the sixth male player in the open era to win three Majors in a calendar year.

He is the first male player representing Serbia to win a Major singles title and the youngest player in the open era to have reached the semifinals of all four Grand Slam events, separately and consecutively. Amongst other titles, he won the Tennis Masters Cup in 2008 and was on the team which won the 2010 Davis Cup. He also won the bronze medal in singles at the Beijing Olympics in 2008. He has won 11 Masters 1000 series titles placing him joint fourth on the all time list. Djokovic has quickly moved up in the rankings of history. Tennis Channel ranked him number 40 , and former player Pat Cash said he is one of the greatest ever.

Rafael "Rafa" Nadal Parera (Catalan: [rəˈfɛɫ nəˈðaɫ pəˈɾeɾə]; Spanish: [rafaˈel naˈðal paˈɾeɾa]) (born 3 June 1986) is a Spanish professional tennis player and a former World No. 1. As of 28 May 2012 (2012 -05-28)^[update], he is ranked No. 2 by the Association of Tennis Professionals (ATP). He is widely regarded as one of the greatest players of all time; his success on clay has earned him the nickname "The King of Clay", and has prompted many experts to regard him as the greatest clay court player of all time.

Nadal has won ten Grand Slam singles titles, including a record six French Open titles (tied with Bjorn Borg), the 2008 Olympic gold medal in singles, a record 21 ATP World Tour Masters 1000 tournaments, and also was part of the Spain Davis Cup team that won the finals in 2004, 2008, 2009 and 2011. He completed the Career Grand Slam by winning the 2010 US Open, being the seventh player in history, and the youngest in the open era, to achieve it. He is the second male player to complete the Career Golden Slam (winner of the four grand slams and the Olympic Gold medal) after only Andre Agassi.

Grigor Dimitrov (Bulgarian: Григор Димитров; born May 16, 1991, in Haskovo) is a tennis player from Bulgaria. He achieved a career high ranking of World No. 52 on August 22, 2011. Dimitrov also enjoyed a very successful junior career, in which he held the World No. 1 ranking and won the boy's singles titles at the 2008 Wimbledon Championships and the 2008 US Open.

Grigor was born in Haskovo, Bulgaria as the only child of father Dimitar, a tennis coach and mother Maria, a sports teacher and former volleyball player. He first held a tennis racket, given to him by his mother at the age of three and when he was five he began to play daily. During his teenage years he lived in Paris, France while training at Patrick Mouratoglou's Tennis Academy. He speaks fluent Bulgarian and English and says his main interests are all sports, cars, computers and watches.

His first major junior coup was when, at aged 14 he claimed the U14 European title. In 2006 he won the Orange Bowl U16 boys singles and was later named the Eddie Herr International 2007 Rising Star.

Fabio 'The Fog' Fognini (born 24 May 1987 in Sanremo, Italy) is a professional tennis player and the current Italian No. 2. His career-high singles ranking is World No. 32, which he reached on June 20, 2011 after reaching the quarter-finals of the 2011 French Open. His favourite surface is the red clay of Paris, where he also reached the quarter-finals as a junior in 2004.

Fognini was born to Silvana and Fulvio, a businessman, and has a younger sister called Fulvia. He began playing tennis when he was four years old and is also a fan of football and motorbike racing. Fognini speaks Italian, English, Spanish and French.

Fognini began his professional career by playing a variety of Futures and Challenger tournaments, winning his first Futures title in 2005 at Spain #1 and another at Italy #9. In 2005, he also finished runner-up at Italy #3 and qualified for his first ATP Challenger tournament at Palermo. During 2006, Fognini had moderate success at Challengers and, after qualifying, made his debut on the ATP World Tour at Buenos Aires. He was defeated in the first round by Carlos Moyá, the eventual champion.