They can move audiences to tears with their inspirational performances, but few can put their finger on that indefinable something that marks out a great conductor.
Indeed, the maestros themselves are sometimes reluctant to even try, preferring instead for their music to speak for them.
At this month's Enescu music festival in Bucharest, however, three famous conductors, Daniel Barenboim, Lawrence Foster and Tiberiu Soare, agreed to explain what they considered to be the essence of their craft.
"Music is something that can unite the thoughts, the feelings and the temper, or, in other words, the head, the heart and the stomach. This is what I try to reach when I conduct," Barenboim told AFP ahead of a series of concerts in Bucharest with the Berlin Staatskapelle orchestra.
Born in Argentina in 1942 to Jewish parents, Barenboim was hailed as a "phenomenon" at the age of 11 by the legendary German conductor Wilhelm Furtwangler.
Since then he has conducted leading European and American symphony orchestras and set up the West-Eastern Divan Orchestra bringing together musicians from all over the Middle East.
"Music is the result of a connection between various elements," he said.
But to get there, you have to "think", he added, rejecting the idea of simply "rehearsing mechanically for many hours."
"For example, if you have a crescendo, it is not sufficient to play louder, you have to know how much and how far you will go," he said.
Romanian Soare, conductor at the National Opera in Bucharest, said he shared Barenboim's ideas.
"To interpret well, you cannot only execute, you have to be able to make imaginary connections" between the various elements of a work, said the 34-year-old conductor whose career highlights include conducting the London Philharmonic orchestra with Romanian opera singer Angela Gheorghiu.
He also stressed the importance of studying the political and social context of a work in order "to convey the letter and the spirit" of the music.
Once all the elements are linked, "this gives an extraordinary feeling of achievement. It is a moment of grace, when you feel like flying," he said.
US conductor Foster, who was musical director of the San Francisco Ballet at the tender age of 19, said he believed it was "important to understand why composers wrote what they did in the manner they did because music is a constant dialogue.
"I feel I understand better, approaching 70, how this dialogue works," he told AFP before conducting the Lisbon-based Gulbenkian orchestra.
"If I can somehow convey the emotional and architectural intent of the composer, I did a good work," he added.
Foster disliked piano lessons when he was a child but was influenced by an older student with whom he played chess.
"He loved classical music, I looked up to him and I thought if he likes classical music, then it is OK."
The revelation that he wanted to be a conductor came when he was 12 and saw the Los Angeles Philharmonic Orchestra for the first time.
"I was so impressed by the idea of 100 musicians making this sound together," he said.
Each of the three conductors has his own method of preparing for a concert.
Soare said he liked to smoke and play Bach or Mozart on the piano, while Foster preferred to rehearse in the morning and then eat some pasta and sleep.
"I eat if I am hungry, sleep if I am tired", said Barenboim, adding though that he always refrained from smoking his beloved cigars until after a concert.
All three remain driven to constantly improve their performance and admit that even they have off days.
"I did bad concerts but I always learned something," said Bareneboim, while Foster stressed that being completely satisfied with a performance would rob him of the will to achieve greater heights.
"We cannot have exceptional moments at every concert but our duty is to try and create these moments every time we conduct," added Soare.
The Enescu music festival runs until Sunday. www.festivalenescu.ro