Major amendments to the Delaware General Corporation Law were made in 1967. The new law was drafted by the Delaware Corporation Law Revision Committee. Information on the work of this Committee can be found in Review of the Delaware Corporation Law by Ernest L. Folk (commonly called the Folk Report) and the Committee’s Minutes and Reports.
When doing legislative history of a section of the Delaware General Corporation Law it is easiest to start with a treatise on Delaware corporation law. The two standard treatises are:
R. Franklin Balotti and Jessie Finkelstein. Delaware Law of Corporations and Business Organizations. Wolters Kluwer (Reserve KFD213 .B35) and
Edward P. Welch, Andrew J. Turezyn, Robert S. Saunders. Folk on the Delaware General Corporation Law. Wolters Kluwer (Reserve KFD213 .F59).
Both sources give a history of each code section (usually to the 1960s or 1970s), and reproduce the synopsis notes from amending bills.
Delaware Laws Governing Business Entities. Corporation Service Company. (Reserve KFD213.A29 D45) also includes changes to the General Corporation Law for each year with synopsis notes.