The book “I Quattro libri del architettura” writen by Andrea Palladio in 1570 can be found in the ETH-Bibliothek but is not available to public use.
Further a newer edition of the book is located in the ETH-zürich, Baubibliothek: location/signature – 61 | 9333 and in the Zentralbibliothek Zürich: 4.UG, FQ 11070
Additionally the PDF of the original book is available in E-rara.
https://www.e-rara.ch/doi/10.3931/e-rara-363