First published in 2000. This is Volume VI of six in the Library of Philosophy series on the Philosophy of Science. Written in 1929, using the initial ideas of A.N. Whitehead, this book on Biological Principles includes the concept of abstraction methodology in biology. This expands into an investigation into the general problems of the theory of knowledge, difficulties in biological knowledge and finally suggestions towards a resolution of certain traditional biological conflicts.

Published with the aid of a grant from the National Endowment for the Humanities. Contains the only complete English-language text of The Concept of Truth in Formalized Languages. Tarski made extensive corrections and revisions of the original translations for this edition, along with new historical remarks. It includes a new preface and a new analytical index for use by philosophers and linguists as well as by historians of mathematics and philosophy.