At the end of last season, Cook sent his recruitment team to go and watch him before securing his signature.
The central midfielder, 23, joined on a free transfer from Dorking Wanderers earlier this month.
Cook knows a lot about him, but many Chesterfield fans won’t’. So who is he?
We spoke to Dorking Wanderers match reporter, Dan Stobbart, to get the inside track on him...
How did he perform in his time at Dorking?
Darren joined Wanderers approaching mid-way through the campaign, signing for the club in November. He immediately locked down a place in the side, and would go on to be a key player in the promotion-winning campaign. He was ever-present in the side that won 10 league games in a row in December/January and also played a big part in the club winning the Surrey Senior Cup for the first time.
How would you describe him as a player?
He is a technically-gifted central midfielder, a playmaker who likes to get on the ball and dictate the tempo. The most notable thing is his strong passing game, particularly his long-range distribution to find and release players in the channels. Like all the good central midfield players he has that knack of finding space for himself and can retain the ball comfortably under pressure as well.
What are his strengths?
In addition to his passing ability and retention of the ball he is a clinical and cool customer when it comes to set-pieces as well. He has scored a couple of free kicks from range including being the match winner in the tight 1-0 home win over fellow promotion chasers Oxford City, and became the club's penalty taker through the course of the season, scoring each time including the equaliser in the Surrey Senior Cup final. You can see in his demeaner on the field and the way he plays that he is very composed and does not let emotion get to him.
What areas could he improve on?
In terms of improvement I think consistency would be the key thing for Darren, reflected in moving round various clubs before joining Wanderers and by the fact he did come out of the starting 11 towards the end of last season as manager Marc White opted for more experience in that area. You forget how young he is though, still only 23, and I'm sure he will continue the upward trajectory and momentum he has built up with Wanderers as he now moves back to full-time football.
What's his best position?
For Wanderers we have only seen him play in the one position, deployed as the deep-lying midfielder sat in front of the back 3. I think by his own admission this position is the area he likes to play in and he has certainly proved he has the attributes to play there.
What formation does he best suit?
To adapt to the Wanderers 3-5-2 formation and very cemented style of play as quickly as he did, arriving mid-way through the season, is again testament to his quality and character. The formation suited him very well, but I can imagine in a 4-2-3-1, which I know Paul Cook has played often at his clubs, he would complement a more robust defensive midfielder in front of the back four effectively as well.
Did it come as a surprise that a club like Chesterfield came in for him or was it expected?
I think the feeling across the club was that there was a good chance Darren was likely to be picked up in the close season by a more established National League club or even a Football League side. Given how quickly he fitted in and demonstrated his quality the move to Chesterfield has not come as a surprise.
He has played in the Football League before - do you think he is capable of getting back there again?
Off the back of such a successful time with Dorking and now keeping that momentum going with a full-time football move to a more established side, I don't see why he cannot continue on that upward trajectory and get back to the Football League in the not too distant future.