WorldCat can be used to find books not held by Penn or in E-ZBorrow/Borrow Direct, that you can borrow via Inter-Library Loan. It will also indicate if a book is held by Penn, and provide a Franklin link to the book if so.
CiNii Books is best for finding books located in Japan, because it searches across Japanese library catalogs, but can be helpful for finding information about books (including how to read the title and author's name), links to Webcat Plus and National Diet Library catalog, and sometimes provides tables of contents for multi-author books.