The book may have numerous typos or missing text. It is not illustrated or indexed. However, purchasers can download a free scanned copy of the original rare book from the publisher's website. You can also preview the book there. Purchasers are also entitled to a trial membership in the publisher's book club where they can select from more than a million books for free. Original Publisher: American Association for the Advancement of Science Publication date: 1920 Subjects: Science; Science / General; Science / History; Science / Reference; Science / Philosophy