More quotes by Mark Twain

"The secret source of humor is not joy but sorrow; there is no humor in Heaven."
"When we remember we are all mad, the mysteries disappear and life stands explained."
"The trouble is not in dying for a friend, but in finding a friend worth dying for."
"I was gratified to be able to answer promptly, and I did. I said I didn’t know."
"In a good bookroom you feel in some mysterious way that you are absorbing the wisdom contained in all the books through your skin, without even opening them."