Chesterfield have appointed Dean Saunders as their new manager on a two-year contract following Paul Cook's departure for Portsmouth.
Cook left the Spireites on Tuesday having guided them to the League One play-offs, where they lost to Preston.
Saunders, 50, ended the season in interim charge of Crawley but was unable to prevent them from being relegated to League Two.
The ex-Wales international previously managed Wrexham, Doncaster and Wolves.
Saunders told the club website: "It is a great opportunity as this is a club on the rise, run by good people, and I am inheriting a very good team from Paul Cook.
"Taking over now gives me a full pre-season to make a fresh start, put my plans in place and work with the squad, which is a great position to be in."
Crawley's relegation means Saunders has now suffered relegation in three of the last four seasons. He was in charge when Doncaster were relegated from the Championship in 2012 and suffered the same fate with Wolves the following year.
He took charge of the Red Devils on an interim basis in December after John Gregory stepped down to undergo major open heart surgery.
Saunders won eight of his 24 league games in charge but they suffered relegation on the last day of the season and Gregory then announced on Saturday that he would not be returning to the club.
Saunders faces a difficult task in succeeding Cook after he guided Chesterfield to the League Two title and a sixth-placed finish in League One in his two full seasons in charge.