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.
The ATP requested and got the MIPTC to introduce a drug testing rule, making tennis the first professional sport to institute a drug-testing program.
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 2009 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 Emirates ATP Rankings is used for determining qualification for entry and seeding in all tournaments for both singles and doubles. Within the Emirates ATP Rankings period consisting of the past 52 weeks, points are accumulated, with the exception of those for the Barclays 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 Emirates 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 BNP Paribas Masters will qualify for the Barclays 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 10 February, 2014
Brad Drewett was the Executive Chairman and President of ATP until he died on 3 May 2013, with Mark Young as the CEO of Americas, Laurent Delanney as the CEO of Europe while Alison Lee leads the International group.
The 7-member ATP Board of Directors includes the Executive Chairman & President (a position that has been empty since the death of former position holder Brad Drewett) 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 Edges 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.