Cloning was first published in 1985. Minnesota Archive Editions uses digital technology to make long-unavailable books once again accessible, and are published unaltered from the original University of Minnesota Press editions.

Cloning has become in recent years a subject of widespread speculation: the word is a source of fear and wonder, the concept a jumping-off point for the fantasies of cartoonists, film producers, and novelists. With this book, cell biologist Robert Gilmore McKinnell provides the first clear scientific explanation of the procedure for general readers.

Cloning is best defined as the asexual reproduction of genetic duplicates. The word clone derives from the Greek word for a twig or a slip, and the first "cloners" were in fact horticulturalists. Early attempts to clone animals culminated in 1952 when biologists reported that they had produced frogs by transplanting genetic material from an embryonic body cell into an egg from which the nucleus had been removed.

In this account, McKinnell traces the historical background of cloning and describes in detail the modern procedure used in the cloning of frogs—the highest animal thus far cloned. He emphasizes that the purpose of cloning is not to produce numerous frogs—or people—but rather to serve as a tool in biological research—to achieve greater understanding of cancer and aging, immunobiology and the differentiation of cells.

McKinnell also deals with questions about potential mammalian clones and examines the social, ethical, and biological problems we face in our considerations about human cloning. He concludes that human clones are not necessary for research purposes and that the diversity achieved with sexual reproduction is far more desirable than the sameness of cloned creatures.