Investor-State LawGuide This link opens in a new window(Scalia Law users only) To access ISLG content, all Mason users must first select "Login," and then click "Auto Login" on the home screen. Next, select "Continue with the NEW ISLG". Investor-State LawGuide (ISLG) is a comprehensive research database for international investment treaty law materials. The ISLG site also features advanced research tools, with reports powered by industry-leading legal analytics, document comparison tools, and more.