From The Atlantic:
Nobel laureate John Steinbeck (1902-1968) might be best-known as the author of East of Eden, The Grapes of Wrath, and Of Mice and Men, but he was also a prolific letter-writer. Steinbeck: A Life in Letters constructs an alternative biography of the iconic author through some 850 of his most thoughtful, witty, honest, opinionated, vulnerable, and revealing letters to family, friends, his editor, and a circle of equally well-known and influential public figures.
Among his correspondence is this beautiful response to his eldest son Thom's 1958 letter, in which the teenage boy confesses to have fallen desperately in love with a girl named Susan while at boarding school. Steinbeck's words of wisdom—tender, optimistic, timeless, infinitely sagacious—should be etched onto the heart and mind of every living, breathing human being.
New York
November 10, 1958
Dear Thom:
We had your letter this morning. I will answer it from my point of view and of course Elaine will from hers.
First — if you are in love — that's a good thing — that's about the best thing that can happen to anyone. Don't let anyone make it small or light to you.
Second — There are several kinds of love. One is a selfish, mean, grasping, egotistical thing which uses love for self-importance. This is the ugly and crippling kind. The other is an outpouring of everything good in you — of kindness and consideration and respect — not only the social respect of manners but the greater respect which is recognition of another person as unique and valuable. The first kind can make you sick and small and weak but the second can release in you strength, and courage and goodness and even wisdom you didn't know you had.
More here.