Walter Keller’s research focused on the biochemical aspects of gene expression, in particular the chemical modifications and processing of ribonucleic acids (RNA) and their precursors in the cell. He also studied the phenomenon of so-called RNA editing, a molecular process of modifying the RNA molecules. He was able to demonstrate that the messenger RNA of the glutamate receptor in our brain is changed by editing, which affects the receptor's properties and communication between nerve cells. In his research, he was also successful in reconstructing extremely complex RNA modifications and to elucidate their importance for protein synthesis. With his work, Walter Keller made significant contributions to the field of RNA research. He was an outstanding researcher, who published over 100 scientific articles and was awarded the Louis-Jeantet Prize for Medicine in 1998 and the Lifetime Achievement Award of the RNA Society in 2007 for his scientific achievements. Walter Keller was also a member of the European Molecular Biology Organization (EMBO), as well as the Academia Europaea.