Kondratiev's theory that Western capitalist economies have long term (50-to-60-year) cycles of boom followed by depression gained recognition inside and outside the Soviet Union.

Nikolai Dimitrievich Kondratiev was born on 4 March 1892 in the Galuevskaya, a village near Vichuga, Kostroma Governorate, into a peasant family of Komi heritage.

[3][4][5] Kondratiev was tutored at the University of St. Petersburg before the 1917 Russian Revolution by Mikhail Tugan-Baranovsky and Alexander Sergeyevich Lappo-Danilevsky.

[6] A member of the Socialist-Revolutionary Party,[2] his initial professional work was in the area of agricultural economics and statistics and the problem of food supplies.

Among the prices studied were raw materials and output products, interest rates, foreign trade, wages, and bank deposits.

In 1924, after publishing his first book, presenting the first tentative version of his theory of major cycles, Kondratiev traveled to England, Germany, Canada and the United States, and visited several universities before returning to Russia.

In his 1924 paper "On the Notion of Economic Statics, Dynamics and Fluctuations", Kondratiev formulated, for the first time, his theory of long business cycles.

The most extensive and devastating wars occurred during periods of an upswing[10](Mager, 1987, p. 27) In 1925 he published his book The Major Economic Cycles, which quickly was translated into German.

A short form was published in 1935 in the Review of Economic Statistics and for a time his ideas became popular in the West, until eclipsed by those of John Maynard Keynes.

People and companies save their resources until confidence begins to return and there is an upswing into a new capital formation period, usually characterized by large scale investment in new technologies.

[2] According to the late Harvard sociologist Carle C. Zimmerman, Kondratiev was reported to Soviet authorities by a member of the University of Minnesota agriculture faculty in 1927 after a visit to sociologist Pitirim Sorokin: Kondratieff (sic), an agricultural economist and student of business cycles, visited Minnesota in 1927 and stayed with Sorokin.

Although his health deteriorated under poor conditions, Kondratiev continued his research and decided to prepare five new books, as he mentioned in a letter to his wife.