This is St. Jerome School's edition of the original Science book for this series. Our edition contains the same material with answer key included in the back, perfect bound paperback copy, 131 pages, including 3 pages for possible drawings from the lessons. This edition also has illustration edits of modesty "fixes" done in lengthening the girls' skirts and more modest bathing suits for the children in congruence with the modesty guidelines of the Catholic Church. We hope you enjoy our "purifying" an old classic. ;) It was made to easily replace OLVS' Science and Living in God's World 1 book.