This book is an interim report on an inquiry that has been ongoing for over twenty years. My ideas first took on a systematic form in 1946 in the book Science, Faith, and Society. In it, I considered science as a variant of sensory perception and developed that vision in three lectures on 'science and reality,' 'authority and consciousness,' and 'dedication or servitude.' But in my Gifford Lectures (Aberdeen, 1951-52), I expanded these themes greatly to include the whole range of knowledge related to the lives of animals and humans. The result was Personal Knowledge (1958), supplemented by a theory of historiography in a small book, The Study of Man (1959). Since then, I have continued this inquiry and have published around twenty essays (listed in the section on related bibliography) as well as written a good number of unpublished texts. The present volume is the first record, in the form of a book, of the work done during the last years." - Michael Polanyi (1966)