Material covers period from 1970 to 1987 when Kenneth A. Cox served MCI as a Regulatory Senior Vice President, with some overlap into earlier years of Cox's service as FCC Commissioner and after his retirement when he was still consulting MCI on regulatory policy. It presents MCI relations with FCC, state utilities commissions, National Association of Regional Utility Commissioners (NARUC), AT&T, Bell Systems Operating Companies (BSOC) and other communications carriers regarding the most essential issues of seventies and eighties telecommunications industry developments: AT&T divestiture arrangements, competitive rates for common carriers, implementation of new technologies. Documents are divided in six groups: 1. FCC filings organized by docket numbers; 2. ENFIA related documents; 3. Appeals of FCC decisions to the U.S. Court of Appeals; 4. Regulatory subject files; 5. States regulatory agencies and NARUC documents; 6. Speeches collected by Cox.