Look at the Volhynia page from the Jewishgen Ukraine Special Interest Group
The book The Journeys of David Toback (Schocken Books, 1981) provides an invaluable glimpse of Jewish life in Shumsk and Volhynia at the end of the 19th century in all its difficulty. You can find out-of-print copies of the book fairly easily. Read a review.
Lynne Tolman has placed an interview
with her cousin Zev Berg (born in Shumsk
in 1919) on the Web.
Lynne has also placed a Shumsk necrology on the
Web.