The Long Waves in Economic Life - Hardcoverby Nikolai D. Kondratieff (Author) The Long Waves In Economic Life is a book written by Nikolai D. Kondratieff, a Russian economist who proposed the theory of long economic cycles. The book explores the idea that the capitalist system experiences long term cycles of expansion and contraction, with each cycle lasting around 50 60 years. Kondratieff argues that these cycles are driven by technological innovation and changes in the structure of the