Maurizio Sarri uncovered: From asking players to learn 38 set-pieces and flying drones to film training to once smoking five packets of fags a day.
Massimo Maccarone appreciates the value of goals. Two he scored against England Under 21s propelled him into the Italy team and sparked a move to Middlesbrough, where they didn't always flow so freely.
Even so, he became the hero of their thrilling charge to the UEFA Cup final in 2006 with late strikes in the quarter-final and semi-final ties.
Big Mac, as he is known in Italian football, has always traded in goals. Last season he was scoring them for Brisbane Roar in Australia and although 39 next month he is about to start a new adventure with Carrarese in Serie C.
But in all those years he has never scored goals like he did playing for Maurizio Sarri at Empoli.
'Sarri is special for strikers,' says Maccarone. 'He wants to play in the attacking half of the pitch. At Naples they say he told Gonzalo Higuain, "If you want to score a lot of goals then do as I say". Higuain was very happy to work with him.
'With him at Empoli, I scored 42 in three years. My partner Francesco Tavano scored even more.'
Higuain, having scored a respectable 18 in 37 games for Napoli in the final year under Rafa Benitez, set a Serie A record with 36 in 35 in his first season under Sarri. The Argentine celebrated another 24 in the next season and earned a move to Juventus for £80million.
Sarri's years at Empoli marked his breakthrough. He took them into the top flight and kept them up against the odds with a young team and a range of managerial skills acquired in the lower reaches of Italian football.
Once estimated to smoke five packets of cigarettes a day, he was quiet, thoughtful and very superstitious, according to Maccarone.
If they lost away, he would never return to the same hotel. If they won, the details of the way they trained would remain the same. They won more than they lost.
'Good times,' says Maccarone. 'They had a lot of young players when I went back. The season started very badly. After 10 games, we had only seven points. But then we started to win and win and win and we reached the play-offs. One year after, we won promotion.'
Many of those who thrived under Sarri at Empoli have enjoyed successful careers, including Juventus centre half Daniele Rugani and Inter Milan midfielder Matias Vecino, both now among the names on Chelsea's wish list.
Others followed the coach to Napoli, including defenders Elseid Hysaj, Mario Rui and Lorenzo Tonelli, and Mirko Valdifiori. 'Sarri is very good at developing young players,' says Maccarone. 'When we went up, only two of us had experience of playing in Serie A. But everyone knew exactly what to do and all the players were with him. I am not surprised by his success. I know he's a good coach.
'He worked very hard with the defence and we played without fear. Even when we went to the big clubs we attacked them. He wasn't scared.
'His thing is to play always with one and two touches. He likes to see the ball moving fast. I think it is fun. You are very lucky to have him in England. When you look at the best football in Europe in the last few years it comes from Sarri and Pep Guardiola.'
Sarri's track record with youngsters was part of the appeal for the Chelsea board, who are yet to crack the puzzle of transforming a wealth of teenage talent into first-team players.
He has been impressed in pre-season by 17-year-old striker Callum Hudson-Odoi and is keen to give him a chance.
A man with socialist principles, he expects others to commit to the common cause because he believes in the power of unity, and Willian's late return from Brazil due to a problem with his passport won't have been well received.
Like Antonio Conte, Sarri scrutinises video footage. At Napoli he used drones to film training sessions from above. At FC Sorrento, they recall how he worked like a 'maniac', always impatient for more tapes to scour.
'He was obsessed with his work,' says their vice-president Michele Mauro. 'Sometimes it can seem difficult to have a relationship with him because he is so very serious but he is a good man, and this work ethic is the secret to his success.'