This fourth book in the series of elementary science readers is a continuation of the previous first book (ED623220), second book (ED623221), and third book (ED623222), with a different emphasis. The central theme of this book is man in his struggle for adjustment to the earth as his home with emphasis upon organized effort and social adjustment. The part that science has played in this organized effort is kept constantly in the foreground. The book might be characterized as an attempt to indicate the part science has played in man's struggle for adjustment. The authors have not attempted to cover the whole field, but have selected outstanding examples for the purpose of giving the elementary school child the feeling of appreciation and understanding of this effort at adjustment. The technique of teaching this material may be left to the teacher and school administrator who are seeking to enrich the school program with this kind of concrete material. Added to each chapter a list of suggested questions to aid the teacher in the effective use of the texts.