从上一世纪中期起,科学工作者就发觉资本主义经济包含着“景气”与“不景气”时期,较高增长率和较低增长率的交替。与每7—11年发生的通常生产过剩危机不同,持久性的(经济)衰退平均每40—50年出现一次。20世纪初,德国、荷兰和俄国的马克思主义者就开始谈到经济长波的存在。然而,正是在20年代,苏联经济学家N·康德拉捷夫提出了一个关于“经济长周期”的概念。康德拉捷夫与“康德拉捷夫周期”康德拉捷夫出身于普通农民家庭,大学毕业后,担任二月革命后临时政府的粮食部副部长。十月革命后,他放弃政治活动而致力于科研工作, Since the middle of the last century, scientists have found that the capitalist economy includes the alternations of higher growth rate and lower growth rate during the “boom” and “downturn” periods. Unlike the usual crisis of overproduction that occurs every 7-11 years, persistent (economic) recessions occur on average every 40-50 years. At the beginning of the 20th century, the Marxists in Germany, the Netherlands and Russia began to talk about the existence of a long wave of economy. However, it was exactly in the 1920s that Soviet economist N. Kantlayev proposed the concept of a “long cycle of economy.” Kondratief and the “Kondlajev Cycle” "Kondlajev was born in a family of ordinary farmers, after graduating from college, served as Deputy Minister of Food for the interim government after the February revolution. After the October Revolution, he abandoned his political activities and devoted himself to scientific research.