This text is a second, revised edition of the original 1986 publication. Since that time, the issue of contract change has increasingly challenged the business community and legal practitioners. This edition studies the investor-host country relationship, on which successful investment is most dependent. In particular, the book studies the pressure by host countries for contract change and its counterpart - the investor's defence of contract stability. The book is essentially a reference handbook for legal practitioners. It analyzes a variety of increasingly important questions concerning international investment agreements that come under pressure for change by one of the contracting parties - either a transnational corporation or a host country government.