Is Sir Alex really the greatest manager of all time?

Fergie and Guardiola

Sir Alex Ferguson's decision to retire at the end of the season got us thinking how he compares with other managers in the pantheon of all time greats.
He won 38 trophies in a 26-year spell at Old Trafford. That included 13 league titles, two Champions Leagues, five FA Cups and four League Cups. Prior to that Fergie tasted glory in Scotland, first with St Mirren where he won the first division title in 1977, and then Aberdeen, with three Scottish Premier Division titles, four Scottish Cups, three League Cups, and that famous European Cup winners Cup victory over Real Madrid in 1983.
There can be little doubt that he is very high on the list, but who else can lay claim to be "the greatest manager of all time"? How do the rest measure up to Sir Alex, and how does he measure up to them?

Let's look at the statistics, and you can make your own minds up...