Write only of what is important and eternal.

When asked, "Why do you always wear black?", he said, "I am mourning for my life.

Here I am with you & yet not for a single moment do I forget that there's an unfinished novel waiting for me.

Not only after two or three centuries, but in a million years, life will still be as it was; life does not change, it remains for ever, following its own laws which do not concern us, or which, at any rate, you will never find out. Migrant birds, cranes for example, fly and fly, and whatever thoughts, high or low, enter their heads, they will still fly and not know why or where. They fly and will continue to fly, whatever philosophers come to life among them; they may philosophize as much as they like, only they will fly.

If you can't distinguish people from lap-dogs, you shouldn't undertake philanthropic work.

When you describe the miserable and unfortunate, and want to make the reader feel pity, try to be somewhat colder - that seems to give a kind of background to another's grief, against which it stands out more clearly. Whereas in your story the characters cry and you sigh. Yes, be more cold. ... The more objective you are, the stronger will be the impression you make.

I am writing a play which I probably will not finish until the end of November. I am writing it with considerable pleasure, though I sin frightfully against the conventions of the stage. It is a comedy with three female parts, six male, four acts, a landscape (view of the lake), lots of talk on literature, little action and tons of love.