I first learned the theory of distributions from Professor Ebbe Thue
Poulsen in an undergraduate course at Aarhus University. Both his
lectures and the textbook, Topological Vector Spaces, Distributions and
Kernels by F. Treves, used in the course, opened my eyes to the beauty
and abstract simplicity of the theory. However my incomplete study of
many branches of classical analysis left me with the question: Why is
the theory of distributions important? In my continued studies this
question was gradually answered, but my growing interest in the history
of mathematics caused me to alter my question to other questions such
as: For what purpose, if any, was the theory of distributions originally
created? Who invented distributions and when? I quickly found answers to
the last two questions: distributions were invented by S. Sobolev and L.
Schwartz around 1936 and 1950, respectively. Knowing this answer,
however, only created a new question: Did Sobolev and Schwartz construct
distributions from scratch or were there earlier trends and, if so, what
were they? It is this question, concerning the pre- history of the
theory of distributions, which I attempt to answer in this book. Most of
my research took place at the History of Science Department of Aarhus
University. I wish to thank this department for its financial and
intellectual support. I am especially grateful to Lektors Kirsti
Andersen from the History of Science Department and Lars Mejlbo from the
Mathematics Department, for their kindness, constructive criticism, and
encouragement.