This book, "Cykloiden Und Cykloidalen Als Umhüllungskurven Und Deren Zusammenhang Mit Den Fusspunktkurven Der Kegelschnitte (German Edition)", by Richard Blum, is a replication. It has been restored by human beings, page by page, so that you may enjoy it in a form as close to the original as possible. This book was created using print-on-demand technology. Thank you for supporting classic literature.