Like beauty, greatness is often in the eye of the beholder. For a select few, it is unquestionable.
When Sir Alex Ferguson announced his retirement, it was beyond dispute that he ranked among football's finest managers. Quite where he belongs in the pantheon is another matter. Some would still say Sir Matt Busby remains the outstanding figure in Manchester United's history. His influence and importance cannot be measured simply by examining what he won.
If silverware is the main criteria, however, then Ferguson stands alone. And if securing trophies outweighs other achievements, then four Premier League clubs had their greatest ever manager last season. Despite Arsenal's long wait for honours, Arsene Wenger's early triumphs mean he remains their answer to Ferguson. But while United won the league, the knockout competitions went to outsiders.
And so, while John Toshack achieved three promotions at Swansea and led them to sixth place in Division 1, Michael Laudrup's feat in lifting the League Cup gives him a claim to be their foremost coach. Paul Jewell took Wigan into the Premier League and to their highest league finish as well as reaching a League Cup final. But Roberto Martinez won the FA Cup and so he, too, may have leapfrogged a distinguished predecessor.
As Chelsea prepare to welcome back their favourite manager, Jose Mourinho, for a second spell, an examination of the most successful coach at each of the 20 clubs who were in the Premier League last season shows that - perhaps because some bigger clubs have fallen from grace - many have worked in recent years. Of those who were born in the 19th century, Aston Villa's George Ramsay, Newcastle's Frank Watt and West Brom's Fred Everiss were not really managers as we would understand them today: instead, they were secretary-managers, whose powers were often limited, with the board picking the team. Nevertheless, their record gives them a claim to be their club's greatest. This is why:
Arsene Wenger (1996-)
Why? Won three league titles, four FA Cups, reached the Champions League final in 2006 and secured 17 consecutive top-four finishes. Revolutionised Arsenal, changing their recruitment, reputation and style of play and financed the building of a stadium. His "Invincibles" were the first team for 115 years to complete an English league season undefeated.
George Ramsay (1884-1926)
Why? Won six league titles and six FA Cups, leaving Villa as the most storied and prestigious club in the country. Under Ramsay, they were only the second club to do the double. Only Sir Alex Ferguson has won more league titles and no manager has lifted the FA Cup more often.
Jose Mourinho (2004-07)
Why? Won two league titles, two League Cups and the FA Cup, reaching two Champions League semi-finals. Walked into a club who had won knockout competitions but no league title for almost 50 years and created a team of dominant winners. Got a record point total in the Premier League - 95 - in 2004-05.
Howard Kendall (1981-87, 1990-93, 1997-98)
Why? In his fruitful first spell at Goodison Park, Kendall won two league titles, the FA Cup and the Cup Winners' Cup. Many an Evertonian thinks that, had they been allowed to enter the European Cup in 1985-86, Kendall's side would have won that, too.
Roy Hodgson (2007-10)
Why? When Hodgson took Fulham to seventh place in 2009, it was their highest-ever league finish. That, however, pales into comparison with what followed. They defeated Juventus and Shakhtar Donetsk en route to the UEFA Cup final the following season. Hodgson also reached two FA Cup quarter-finals.
Bob Paisley (1974-83)
Why? The only manager ever to win three European Cups, Paisley's brief managerial career was also arguably the most glorious nine years any English club has ever had. He won six league titles, three League Cups and the UEFA Cup, taking Bill Shankly's team and making them more dominant in both England and Europe.
Joe Mercer (1965-71)
Why? Mercer oversaw the most celebrated spell in City's history, winning promotion to the old Division 1 and, between 1968 and 1970, the league title, the FA Cup, the League Cup and the Cup Winners' Cup, building a stylish team who played fine football. He was part of a great managerial double act with assistant Malcolm Allison.
Sir Alex Ferguson (1986-2013)
Why? Thirty-eight trophies, a record 13 league titles, five FA Cups, four League Cups, two Champions Leagues... the list is endless. Inherited underachievers and turned United into the most successful club in the history of domestic English football with attacking play, a wonderful youth system and some superb signings.
Frank Watt (1895-1932)
Why? One of the old-style secretary-managers, Watt's mammoth 37-year reign included a spell before World War I when Newcastle became the team to beat in England. They won the league three times in five years and reached five FA Cup finals out of seven.
Ken Brown (1980-87)
Why? Brown took Norwich to fifth, then their highest ever league finish, in his last full season at Carrow Road. Although relegated twice in his time in charge, they were also promoted twice and won the League Cup in 1985, one of only two major trophies in their history.
Dave Sexton (1974-77)
Why? QPR finished second in 1976, a point behind champions Liverpool, after winning 13 of their final 15 league games. Sexton's classy side also reached the semi-finals of the League Cup and, in Rangers' best European performance, the quarter-finals of the UEFA Cup, earning him a move to Manchester United.
Steve Coppell (2003-09)
Why? The first manager in Reading's long history to take them into the top flight and the only one to keep them there. Their eighth-place finish in 2007 is by far and away their finest league achievement and testament to Coppell's ability to identify players and build a team on a slender budget.
Lawrie McMenemy (1973-85)
Why? Won Southampton's only major trophy, the 1976 FA Cup, as a second-division side. Then won promotion to the top flight, reached the League Cup final and achieved the Saints' highest league finish - second - in 1984. Brought a series of big-name players to a club that did not have a tradition of glory.
Tony Waddington (1960-77)
Why? Oversaw the best spell in Stoke's 150-year history, winning the League Cup and being beaten finalists, twice reaching the FA Cup semi-finals and, after securing promotion, twice finishing fifth in Division 1. Unlike another managerial Tony at Stoke, Waddington's teams were admired because they featured flair players and mavericks.
Tom Watson (1888-96)
Why? Until Watson left for Liverpool, Sunderland were the Football League's most successful side, winning three titles in five seasons and also reaching three FA Cup semi-finals. Unlike the other secretaries and administrators of his era, he is considered one of the first modern managers.
Michael Laudrup (2012-)
Why? Won Swansea's first major trophy, the 2013 League Cup, and took them to their highest league finish in more than 30 years - ninth place - last season. Earned plaudits for his passing style of play and his acumen in the transfer market.
Bill Nicholson (1958-74)
Why? Made Tottenham one of the most attacking and glamorous teams in the country. They were the first side in the 20th century to do the double in 1961 and were specialists in knockout competitions, winning three FA Cups, two League Cups, the UEFA Cup and the Cup Winners' Cup as well as the league, scoring 115 goals in their title-winning campaign.
West Bromwich Albion
Fred Everiss (1902-48)
Why? The longest-serving manager in the history of the Football League - even if, as a secretary-manager, he did not enjoy complete control - Everiss' 46-year reign included Albion's only league title, in 1920, plus the FA Cup and two promotions.
West Ham United
Ron Greenwood (1961-74)
Why? In three wonderful years, Greenwood's West Ham won the FA Cup, the Cup Winners' Cup and the World Cup (well, Bobby Moore, Martin Peters and Geoff Hurst did, anyway). A passing team who entertained spectators, his side had a highest finish of sixth place. West Ham's fine football helped Greenwood later become England manager.
Roberto Martinez (2009-2013)
Why? Won Wigan's first major trophy, the 2013 FA Cup, and, despite their eventual relegation, Martinez is the only manager to keep them in the Premier League three times. Also secured the club's first ever victories against Manchester United, Chelsea and Liverpool.