Has research/thought on Russian literature and cultural history changed much over the past several generations, or would books from earlier times still retain substantial scholarly merit/relevance? For examples of the type of books I'm asking about:
Isabel Hapgood - A Survey of Russian Literature (1902)
Maurice Baring - Landmarks in Russian Literature (1910)
Evar Spector - An introduction to Russian history and culture (1954)
Are you asking because you're writing an essay for college level upper division essay?
If so, and it were me, I would research and find out the various academic schools of thought, and definitely look in respected scholarly journals for essays. Those sources look a little too dated to be used as the foundation for a good research paper, but I've not studied Russian lit crit specifically, but in general it has changed tremendously in the last generations, and different schools of thought can be used to analyze literature.
Happened upon this site: http://muse.jhu.edu/books/9780822977445
It has a chapter on emigre literary crit, which might add an additional insight in an essay, though one might have to analyze whether that body of work influenced the wider standard academic field.
Here's a Boston University reading list for a lower division course that has what looks to be some standard works on Russian culture from American academia: http://www.bu.edu/library/guide/wr150russian/
I used to love writing research papers, but it's been awhile. Research methods can't have changed all that much though.
The field of history is definitely changing. One book I like is "Keeping the Faith: Russian Orthodox Monasticism in the Soviet Union, 1917-1939" by Jennifer Jean Wynot, PhD, University of Texas Press. Not what you're looking for right now, but thought you might find it interesting at some point.