The bulk of the present book has not been published previously though
Chapters II and IV are based in part on two earlier papers of mine: "The
Influence of Harald H!1lffding's Philosophy on Niels Bohr's
Interpretation of Quantum Mechanics", which appeared in Danish Yearbook
of Philosophy, 1979, and "The Bohr-H!1lffding Relationship
Reconsidered", published in Studies in History and Philosophy of
Science, 1988. These two papers comple- ment each other, and in order to
give the whole issue a more extended treatment I have sought, in the
present volume by drawing on relevant historical material, to
substantiate the claim that H!1lffding was Bohr's mentor. Besides
containing a detailed account of Bohr's philosophy, the book, at the
same time, serves the purpose of making H!1lffding' s ideas and
historical significance better known to a non-Danish readership. During
my work on this book I have consulted the Royal Danish Library; the
National Archive of Denmark and the Niels Bohr Archive, Copenhagen, in
search of relevant material. I am grateful for permission to use and
quote material from these sources. Likewise, I am indebted to colleagues
and friends for commenting upon the manuscript: I am especially grateful
to Professor Henry Folse for our many discussions during my visit to New
Orleans in November-December 1988 and again here in Elsinore in July
1990.