The Anna Karenina principle was popularized by Jared Diamond in his book Guns, Germs and Steel to describe an endeavor in which a deficiency in any one of a number of factors dooms it to failure. Consequently, a successful endeavor (subject to this principle) is one in which every last one of the possible deficiencies has been avoided.
<blockquote>Happy families are all alike; every unhappy family is unhappy in its own way.</blockquote>
Diamond uses this principle to illustrate why so few wild animals have been successfully domesticated throughout history, as a deficiency in any one of a great number of factors can render a species undomesticable. Therefore all successfully domesticated species are not so because of a particular positive trait, but because of a lack of any number of possible negative traits.