Heiko Narrog is Professor at the Graduate School of International Cultural Studies, Tohoku University. He received a PhD in Japanese Studies from the Ruhr University Bochum in 1997, and a PhD in Language Studies from Tokyo University in 2002. His publications include Modality in Japanese and the Layered Structure of the Clause (Benjamins, 2009), and Modality, Subjectivity, and Semantic Change: A Cross-Linguistic Perspective (OUP, 2012) as well as numerous articles in linguistic typology, semantics and language change, and Japanese linguistics.
Bernd Heine is Emeritus Professor at the Institute of African Studies and Egyptology, University of Cologne. He has held visiting professorships at universities across the world, and in 2009 received the Lifetime Achievement Award of the Evolutionary Linguistics Association. His many publications include African Languages: An Introduction (CUP, 2000), A Linguistic Geography of Africa (CUP, 2008), and the OUP volumes The Changing Languages of Europe (2006) and The Genesis of Grammar: A Reconstruction (2007), both with Tania Kuteva.
Heiko Narrog and Bernd Heine are co-editors of the OUP volumes The Oxford Handbook of Linguistic Analysis (2010; second edition 2015), The Oxford Handbook of Grammaticalization (2010; paperback 2021), and Grammaticalization from a Typological Perspective (2018).