There is no author's introduction to Phenomenology and the Foundations of the Sciences,! either as published here in the first English translation or in the standard German edition, because its proper introduction is its companion volume: General Introduction to Pure Phenomenology. 2 The latter is the first book of Edmund Husserl's larger work: Ideas Toward a Pure Phenomenology and Phenomenological Philosophy, and is commonly referred to as Ideas I (or Ideen 1). The former is commonly called Ideen III. Between these two parts of the whole stands a third: Phenomeno 3 logical Investigations of Constitution, generally known as Ideen II. In this introduction the Roman numeral designations will be used, as well as the abbreviation PFS for the translation at hand. In many translation projects there is an initial problem of establish ing the text to be translated. That problem confronts translators of the books of Husserl's Ideas in different ways. The Ideas was written in 1912, during Husserl's years in Gottingen (1901-1916). Books I and II were extensively revised over nearly two decades and the changes were incorporated by the editors into the texts of the Husserliana editions of 1950 and 1952 respectively. Manuscripts of the various reworkings of the texts are preserved in the Husserl Archives, but for those unable to work there the only one directly available for Ideen II is the reconstructed one.