'The most revealing letter, though, might be le Carré’s gently discouraging reply, in 1988, to a ten-year-old boy who wanted advice on how to become a spy. He diagnosed his young fan with the same yearning—for adventure, for purpose—that had made Charlie susceptible to her handler’s seduction. “My guess is,” le Carré wrote, “you want excitement and a great cause. But I think and hope that if you ever find the great cause, the excitement will come naturally from the pleasure of serving it, & then you won’t need to deceive anybody, you will have found what you are looking for.”

https://www.newyorker.com/books/page-turner/john-le-carres-search-for-a-vocation