Thank you for checking out this book by Theophania Publishing. We appreciate your business and look forward to serving you soon. We have thousands of titles available, and we invite you to search for us by name, contact us via our website, or download our most recent catalogues. The present volume takes a wide survey of the field of error, embracing in its view no only the illusions of sense dealt with in treatises on physiological optics, etc., but also other errors familiarly known as illusions, and resembling the former in their structure and mode of origin. I have throughout endeavoured to keep to a strictly scientific treatment, that is to say, the description and classification of acknowledged errors, and the explanation of these by a reference to their psychical and physical conditions. At the same time, I was not able, at the close of my exposition, to avoid pointing out how the psychology leads on to the philosophy of the subject. Some of the chapters were first roughly sketched out in articles published in magazines and reviews; but these have been not only greatly enlarged, but, to a considerable extent, rewritten.