Slapstick, or Lonesome No More is a science fiction novel by American author Kurt Vonnegut.

It is concerned with the life story of Dr. Wilbur Daffodil-11 Swain. Dr. Swain is a nearly 7 foot tall mongoloid who, in close physical contact with his twin Eliza, forms a vastly powerful and creative intelligence. This intelligence goes on to create, amongst other things, a plan to end loneliness in America through the creation of vast extended families. Under the plan, all citizens would be provided with a fanciful middle names, paired with numbers. Everyone with the same name would be cousins, and everyone with the same name and number would be siblings. Armed with this idea and the slogan, "Lonesome No More," Dr. Swain wins election to the Presidency, and devotes the waning energies of the Federal government towards the implementation of the plan. In the meantime, Western civilization is nearing collapse as oil runs out, and the Chinese are making vast leaps forward by miniaturizing themselves and training groups of hundreds to think as one.

Often surreal, the novel was written shortly after the death of the author's sister, and seems to be a bizarre meditation on the nature of their closeness. Written in an almost free associative style, the book lacks the structural intracacies of Vonnegut's earlier works.