The Vienna Convention on the Law of Treaties in Investor-State Disputes: History, Evolution and Future is the first consolidated analysis of how the Vienna Convention on the Law of Treaties (VCLT) has informed the interpretation, application and development of international investment law and the resolution of investor-State disputes. Over the past several decades, the VCLT – the ‘treaty on treaties’ – has achieved a rich and nuanced track record of influence in international investment law, including in the context of investment treaty arbitration. This book demonstrates how approaches to key issues of treaty law in investment treaty arbitration diverge or converge from the VCLT and approaches of other international courts, as well as the lessons that investment treaty arbitration could derive from – or even offer for – the interpretation and application of the VCLT rules in other settings.