CapIQ
For Kellogg affiliates only.  Has some company historical data going back to the 1990s.  Access provided by the Kellogg Career Management Center.  Contact them at cmclibrary@kellogg.northwestern.edu

Compustat
For Kellogg affiliates only.  Has company financials going back to the 1950s.  Access provided by Kellogg Research Support.

Datastream
For Kellogg affiliates only.  Has historical information on equities, bonds, derivatives, commodities, warrants and more.  Access provided by Kellogg Research Support.

Doing Historical Company Research: A Resource Guide - from the Library of Congress
Provides resource ideas for locating historical information.