Nikolai Vladislavovich Valentinov (Rusaian: Николай Владиславович Валентинов; 18 May 1880 – 26 July 1964) was a Russian philosopher, journalist and economist.

During these years, Valentinov-Volski undertook a thorough study of Marxism, reading Karl Marx' magnum opus Capital and writings by Georgi Plekhanov and Vladimir Lenin.

He also took an interest in contemporary philosophy of science, especially in the empirio-criticism and empirio-monist theories of Ernst Mach and Richard Avenarius.

(1902), whose vision of a network of working-class activists, skilled at the art of evading police, appealed to the former sympathizer of Narodnaya Volya.

[1] Valentinov objected to this critique, since in his view empirio-criticism was designed to overcome the metaphysical dichotomy of idealism and realism.

Valentinov considered Lenin's position dogmatic, unscientific and based on an inadequate understanding of philosophy.

In this work he rejected the charge of idealism and, in his various philosophical writings, went out of his way to criticise former Marxists like Sergei Bulgakov and Petr Struve, who had embraced idealist philosophies.

During the abortive Revolution of 1905, Valentinov worked for the Ukrainian Menshevik party in various capacities but played a minor role in the political events of the day.

He concentrated primarily on journalism, contributing to such papers as Russkoe Slovo (Russian Word) and Kievskaya Mysl (where Leon Trotsky was one of his colleagues).

He watched the rise of Joseph Stalin with alarm and firmly opposed moves to abandon the NEP in favour of a programme of rapid industrialisation and collectivisation of agriculture.

Valentinov was frequently consulted by scholars (e.g., Leopold Haimson) on the early history of the Russian revolutionary movement and the Soviet Union.