At the age of 17 Crooks was accepted as an apprentice aeronautical engineer at the Royal Aircraft Establishment at Farnborough. This famous British school of aircraft designers has also produced some famous racing names - notably March designer Robin Herd. After five years of studying Crooks joined the staff at the RAE - paying back the company for his education - and for the next five years he worked as a detail designer on aerospace projects - one of his fellow students and later colleagues was another F1 designer Frank Coppuck.Having served his time Paul applied for a job as a detail designer with Toleman Group Motorsport and worked under Rory Byrne for the next six years, becoming the team's chief composite design engineer in 1983.At the end of 1988, however, Guy Ligier had a clearing out of his technical team at Magny-Cours and set about hiring the best men he could find. He picked Brazilian engineer Richard Divila, American Ken Anderson, CAD-CAM ace Andy Willard and Crooks to head the composite design department. In 1992 Crooks became Ligier's chief designer under the new technical director Frank Dernie. Unfortunately the arrest of team boss Cyril de Rouvre sent it into a steep decline and Crooks decided to take up the offer to be chief designer at Simtek Research - the sister company of Simtek Grand Prix.It was Crooks who oversaw the design and construction of the promising Simtek S941 although the team's lack of finance and the death of Roland Ratzenberger meant the car was not able to show its true merit. The team survived until mid-1995 and then Crooks accepted an offer from Dernie to go back to Ligier. The withdrawal from Ligier of Tom Walkinshaw in 1997 put Crooks on the market once again and rather than joining TWR in England he accepted an offer from Jordan Grand Prix to be head of their drawing office at Silverstone. He was later lured away to British American Racing and was then briefly at Minardi.