  This is the written version of a talk given in memory of Gunnar
K\"{a}ll\'{e}n, at the Departments of Theoretical Physics, Physics, and
Astronomy of Lund University on February 13, 2009. It will be published in a
collection of the papers of Gunnar K\"{a}ll\'{e}n, edited by C. Jarlskog and A.
C. T. Wu. I discuss some of K\"{a}ll\'{e}n's work, especially regarding the
problem of infinities in quantum field theory, and recount my own interactions
with him. In addition, I describe for non-specialists the current status of the
problem, and present my personal view on how it may be resolved in the future.
