Tvedt is the author of a wide range of books and articles, has written/co-directed a number of TV-documentaries and been the leader of a number of national and international research networks and research projects. He has done research on three particular areas. His most central area of research is on the relationship between society and what is called “open and complex water society systems”.
Tvedt is series editor as well as co-editor for all the nine volumes in the series A History of Water. He has published a number of books and articles about the history of the Nile Basin, especially focusing on the modern period from the British Nile Empire until today (see for example The River Nile in the Age of the British and The Nile. The River of History). He has also published books based on his award-winning TV-documentaries on water, which are translated into a number of languages.
Tvedt’s other area of research revolves around Norwegian foreign policy, non-governmental organizations, and the growth of the “international aid system” (see for example Angels of Mercy or Development Diplomats) and how it has developed and influenced modern Norwegian institutional and ideological history, giving birth to what is called a national do-gooder regime (see for example Utviklingshjelp, utenrikspolitikk og makt. Den norske modellen).
One last area has been studies of the modern history of Norwegian ideas and mentalities regarding what is commonly called the “developing world” (see for example Images of “the other” (English title) and Woldviews and selfimages (English title).
Tvedt is now finishing a book on the industrial revolution and a book about the River Nile and its long, complex history thorough to current politics, based on his latest TV-documentary.