===Primary sources===
* Croly, Herbert. ''The Promise of American Life'' (1909) [httphttps://books.google.com/books?id=3BASAAAAYAAJ&dq=inauthor:herbert+inauthor:croly&lr=&as_drrb_is=q&as_minm_is=0&as_miny_is=&as_maxm_is=0&as_maxy_is=&num=30&as_brr=1 full text online], one of the most influential books of the early 20th century* Croly, Herbert. ''Progressive Democracy'' (1914) [httphttps://books.google.com/books?id=QBUpAAAAYAAJ&dq=inauthor:herbert+inauthor:croly&lr=&as_drrb_is=q&as_minm_is=0&as_miny_is=&as_maxm_is=0&as_maxy_is=&num=30&as_brr=1 full text online]* Croly, Herbert. ''Marcus Alonso Hanna: His Life and Work'' [httphttps://books.google.com/books?id=jtJBAAAAIAAJ&dq=inauthor:herbert+inauthor:croly&lr=&as_drrb_is=q&as_minm_is=0&as_miny_is=&as_maxm_is=0&as_maxy_is=&num=30&as_brr=1 full text online](1912), favorable biography of the leading conservative politician
* Croly, Herbert. "The Effect on American Institutions of a Powerful Military and Naval Establishment," ''Annals of the American Academy of Political and Social Science'', Vol. 66, (July 1916), pp. 157–172 [http://www.jstor.org/stable/1013440 in JSTOR]
* Croly, Herbert. "State Political Reorganization," ''Proceedings of the American Political Science Association,'' Vol. 8, Eighth Annual Meeting (1911), pp. 122–135 [http://www.jstor.org/stable/3038400 in JSTOR]