The Association of Tennis Professionals (ATP) was formed in September 1972 by Donald Dell, Jack Kramer, and Cliff Drysdale to protect the interests of male professional tennis players. Drysdale became the first President. 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.
In May 1973 Nikola Pilić, Yugoslavia's number one tennis player, was suspended by his national lawn tennis association, who claimed he had refused to play in a Davis Cup tie for his country earlier that month. The initial suspension of nine months, supported by the International Lawn Tennis Federation (ILTF), was later reduced by the ILTF to one month which meant that Pilic would not be allowed to play at Wimbledon. In response the ATP threatened a boycott, stating that if Pilić was not allowed to compete none should. After last-ditch attempts at a compromise failed the ATP voted in favor of a boycott and as a result 81 of the top players, including reigning champion Stan Smith and 13 of the 16 men's seeds, did not compete at the 1973 Wimbledon Championships. Three ATP players, Ilie Năstase, Roger Taylor and Ray Keldie defied the boycott and were fined by the ATP's disciplinary committee.
But the tour was still run by the tournament directors and the ITF. The lack of player representation and influence within the MIPTC as well as dissatisfaction with the way the sport was managed and marketed culminated in a player mutiny in 1988 that changed the entire structure of the tour. CEO Hamilton Jordan is credited with the Parking Lot Press Conference on 30 August 1988 during which the ATP announced their withdrawal from the MIPTC (then called the MTC) and the creation of their own ATP Tour from 1990 onwards. This re-organisation also ended a lawsuit with Volvo and Donald Dell. On 19 January 1989 the ATP published the Tour calendar for the inaugural 1990 season.
By 1991, the men had their first television package to broadcast 19 tournaments to the world. Coming on-line with their first website in 1995, was quickly followed by a multi-year agreement with Mercedes-Benz.
Lawsuits in 2008, around virtually the same issues, resulted in a restructured tour.
The Masters 1000 tournaments are Indian Wells, Miami, Monte Carlo, Rome, Madrid, Toronto/Montreal, Cincinnati, Shanghai and Paris. The end-of-year event, the World Tour Finals, moved from Shanghai to London. Hamburg has been displaced by the new clay court event at Madrid, which is a new combined men's and women's tournament. From 2011, Rome and Cincinnati will also be combined tournaments. Severe sanctions will be placed on top players skipping the Masters 1000 series events, unless medical proof is presented. Plans to eliminate Monte Carlo and Hamburg as Masters Series events led to controversy and protests from players as well as organisers. Hamburg and Monte Carlo filed lawsuits against the ATP, and as a concession it was decided that Monte Carlo remains a Masters 1000 level event, with more prize money and 1000 ranking points, but it would no longer be a compulsory tournament for top-ranked players. Monte Carlo later dropped its suit. Hamburg was "reserved" to become a 500 level event in the summer. Hamburg did not accept this concession, but later lost its suit.
The ATP & ITF have declared that Davis Cup World Group and World Group Playoffs award a total of up to 500 points. Players accumulate points over the 4 rounds and the playoffs and these are counted as one of a player's four best results from the 500 level events. An additional 125 points are given to a player who wins all 8 live rubbers and wins the Davis Cup. 
Additionally, the domain name of the ATP website was changed to "www.atpworldtour.com".
ATP publishes weekly rankings of professional players: Emirates ATP Rankings (commonly known as the ‘world rankings’), a 52-week rolling ranking, and the Emirates ATP Rankings Race to London, a year to date ranking.
The ATP Rankings is used for determining qualification for entry and seeding in all tournaments for both singles and doubles. Within the ATP Rankings period consisting of the past 52 weeks, points are accumulated, with the exception of those for the ATP World Tour Finals, whose points are dropped following the last ATP event of the year. The player with the most points by season's end is the World Number 1 of the year.
The ATP Rankings Race To London is a calendar-year indicator of what the Emirates ATP Rankings will be on the Monday after the end of the regular season. Players finishing in the Top 8 of the Emirates ATP Rankings following the Paris Masters will qualify for the ATP World Tour Finals.
At the start of the 2009 season, all accumulated ranking points have been doubled to bring them in line with the new tournament ranking system.
Current Men's Singles ATP Rankings
ATP Rankings (singles), as of 24 November 2014
Chris Kermode is the current Executive Chairman and President of ATP, succeeding Brad Drewett who died of an illness on 3 May 2013. Mark Young is the CEO of Americas, Laurent Delanney is the CEO of Europe while Alison Lee leads the International group.
The seven-member ATP Board of Directors includes the Executive Chairman & President along with tournament representatives, Gavin Forbes, Mark Webster and Charles Smith. It also includes three player representatives with two-year terms, Giorgio di Palermo as the European representative, David Egdes as the International representative and Justin Gimelstob as the Americas representative. The player representatives are elected by the ATP Player Council.
The ATP Tournament Council consists of a total of 13 members, of which five are representatives from the European region along with another four from the Americas and an equal number from the International Group of tournaments.