Celtic manager Ronny Deila has decided to leave the club at the end of the season.
Here's a look at some of the possible contenders to replace the Norwegian.
The Scot is the favourite with bookmakers to get the job - and is reportedly the board's number one candidate. Now 52, he started his playing career at Celtic in 1980 but left for Cambridge three years later. However, it is as a manager he is best known, managing Preston before a nine-year stint at Everton, which was followed by an ill-fated 10-month reign at Manchester United after Sir Alex Ferguson retired. Out of work since November, when a stint as boss of Real Sociedad ended after 364 days.
The 44-year-old would have his supporters, having largely made a good impression in a four-year reign with the Hoops which ended less than two years ago. A former captain, he guided them to three Premier Leagues and two Scottish Cups, as well as successive appearances in the group stages of the Champions League. Available after an unsuccessful 17-month spell with struggling Bolton - and has admitted he would be interested in the job.
Self-confessed Celtic fan Keane, 44, ended his playing career with the club in 2006 but turned down the chance to succeed Lennon as boss because he did not feel they wanted him enough. He then led Sunderland from the bottom of the Championship to the top but failed to make an impression with them in the Premier League, before an anticipated promotion challenge at Ipswich failed to materialise and he left after less than two years in the job. Currently assistant to former Hoops boss Martin O'Neill with the Republic of Ireland.
In February, Deila was unimpressed with rumours suggesting his replacement would be the 46-year-old former Brechin and Shamrock Rovers boss. O'Neill has impressed in leading Northern Ireland to their first European Championship - the first time in 30 years they have qualified for a major tournament - but that in itself could be an obstacle as his current focus is on Euro 2016. Plus, there are compensation issues with him currently serving a long contract with the Irish Football Association.
The 44-year-old is another to speak positively about the job recently and, like Moyes, available - unlike fellow former Hoops favourites Alan Stubbs and Paul Hartley. The Scot led Cardiff to the Premier League in 2013 but was sacked after a dispute with club owner Vincent Tan. His next appointment, at Wigan, ended a little more than a year ago after five largely disappointing months.