Short answers, pulled from the story.
The Monist was founded by American publisher Edward C. Hegeler and first published in October 1890. It has been issued as a quarterly peer-reviewed academic journal in philosophy ever since, with one gap in publication between 1936 and 1962.
Bertrand Russell's Philosophy of Logical Atomism was first published in full as a series of articles in The Monist in 1918 and 1919. The work became one of the foundational texts of analytic philosophy.
Early contributors included philosophers Charles Sanders Peirce, John Dewey, Gottlob Frege, and Bertrand Russell, as well as scientists and mathematicians Ernst Mach, David Hilbert, Henri Poincare, Alfred Binet, and Ernst Haeckel. The journal was notable for publishing both disciplines together.
The Monist ceased publication in 1936 after Mary Hegeler Carus ended her tenure as editor-in-chief. It resumed publication in 1962 under editor Eugene Freeman, having been absent for more than two decades.
Since January 2015, The Monist has been published by Oxford University Press on behalf of the Hegeler Institute. Each issue focuses on a single pre-announced topic, a format adopted when the journal resumed publication in 1962.
The editors-in-chief have been Paul Carus (1890-1919), Mary Hegeler Carus (1919-1936), Eugene Freeman (1962-1983), John Hospers (1983-1991), Barry Smith of the University at Buffalo (1992-2016), and Fraser MacBride of the University of Manchester (2017 to the present).