Light on Life by B.K.S Iyengar
Imagination - February 20, 2010
"Imagination too can work either to our benefit or to our detriment. It is 
undoubtedly the greatest gift to human beings. But the Sanskrit word vikalapa also means fantasy or delusion. Without steady application, even the most inspiring flights of imagination must remain impotent, devoid of reality. If a scientist has an idea, he may have to labor for years, experimenting, analyzing, and checking in order to bring it to fruition, to make it concrete. A writer may dream of plot for a new novel, but unless he applies himself to pen and paper his ideas have no value. A callow youth once said to a great poet, "I have a marvelous idea for a new poem." The poet replied cuttingly, "Poems are about words." The true poet had his feet on the ground. Never mind the idea, write it down!"
From Light on Life by B.K.S Iyengar - pp. 156-157