Lars is a true giant in both economics and finance. His remarkably general empirical methods free researchers from the need to make a range of empirically implausible statistical assumptions about the data that they are studying. By doing so, Lars' methods allow economists to assess the core economic implications of their models and theories relative to the data of interest.
Lars was my Ph. D. advisor back when I was in Chicago. He was incredibly generous to me with his time and advice when I was a student. He has continued to be a huge source of intellectual support and inspiration in the years since I graduated.