is a Welsh former professional football player and manager.

He began his playing career as a teenager with his hometown club Cardiff City, becoming the youngest player to make an appearance for the side when he made his debut in 1965. After establishing himself in the first-team, he went on to make over 200 appearances and scored 100 goals in all competitions after forming a striking partnership with Brian Clark.

In 1970, he joined First Division side Liverpool, where he formed a noted forward partnership with Kevin Keegan and Steve Heighway that helped the club to win two league titles, the European Cup, the UEFA Cup on two occasions, the FA Cup and the UEFA Super Cup. His partnership with Keegan was so effective that the two were described as telepathic. Mounting injuries eventually led to him securing his release from Liverpool to join Swansea City as player-manager in March 1978. He led the club to three promotions in four seasons, elevating them from the Fourth Division to the First Division in a feat that led former Liverpool manager Bill Shankly to describe him as the \"manager of the century\". During his career, he scored over 150 goals in the Football League in more than 350 appearances and also represented Wales at international level, winning 40 caps and scoring 13 goals.

He resigned from Swansea in 1984 after suffering relegation and embarked on a managerial career abroad, taking charge of Sporting CP in Portugal and later Spanish side Real Sociedad, winning the Copa del Rey in 1987. Two years later, he was appointed manager of Real Madrid and led them to a fifth consecutive La Liga title with a record total of points and goals scored. However, a disappointing start to the following season resulted in his dismissal in November 1990 and he returned to Real Sociedad. In 1994, he was appointed part-time manager of Wales alongside his job at Sociedad but resigned from the role after just 47 days having been in charge for one match, citing the strong support for former manager Terry Yorath among fans and a \"political war\" as reasons. In 1995, he was appointed manager of Deportivo La Coruña during the club's \"Super Depor\" era, reaching the Cup Winners' Cup semifinals in his first season before departing acrimoniously in February 1997.

After a spell in Turkey with Beşiktaş, he returned to Real Madrid for a second time but was sacked ten months later after refusing to retract criticism he had made of his players in a press conference following a defeat. In 2004, he was appointed as manager of Wales for a second time and remained with the side for six years, presiding over three ultimately unsuccessful qualifying campaigns. He later managed Macedonia and Azerbaijani side Khazar Lankaran before managing outside Europe for the first time in his career with Moroccan side Wydad Casablanca and Tractor of Iran.