Can someone tell me where I would find Voter Registration Records for
Cook County, Illinios for the period 1910 - 1940 ?

Yes. Write to to Board of Election Commissioners, Room 308,
City Hall, Chicago IL 60602 fax (312) 263-3649 tel 312-269-7900.

Only thing is verify the area code... this might have changed .

Good luck!
Yigal Rechtman
rechtman@aol.com