Macclesfield Town manager Keith Alexander has died at the age of 53, the club have announced.
Alexander, described by Town as a 'splendid man', passed away after returning home from Tuesday night's match at Notts County.
The thoughts of the League Two club and the entire football world are now with Alexander's family.
A statement from the club said on Wednesday: "It is our sad duty to report that Keith Alexander passed away today after arriving home from Macclesfield Town's game at Notts County last night.
"Keith was a splendid man. He will be sorely missed at the Moss Rose and by everyone involved in football.
"Our thoughts and sympathies are with his family at this very difficult time."
Peterborough director of football Barry Fry, who worked with Alexander at Barnet and London Road, told Sky Sports News: "It is devastating news. You won't find a more dedicated man at any club, non-league or League."
He added: "It is terrible news for everybody in football and everybody who knew Keith because he was a real genuine guy."
Those sentiments were echoed by Macclesfield striker Craig Lindfield, who told Sky Sports News: "I would just like to say I will always be grateful to the gaffer for giving me a chance.
"I trialled at a few clubs and because of the current money situation within football most were not willing to take a chance on me after I left Liverpool.
"Keith gave me that chance to get back playing in the Football League after nearly five months without a club and I will never forget that."
Alexander was universally respected throughout football but his health problems dated back to November 2003, when he suffered a cerebral aneurysm.
Many tributes have been paid to Alexander, who took charge of Lincoln City in 1993 for the first of his two spells at the club.
Nottingham-born Alexander led Lincoln to four consecutive promotion play-off appearances between 2002 and 2006.
Alexander had two stints in charge of Lincoln and spells at Ilkeston Town, Northwich, Peterborough and Bury before his appointment at Macclesfield in February 2008.