From the website: "The National Yiddish Book Center is proud to offer online access to the full texts of nearly 11,000 out-of-print Yiddish titles. You can browse, read, download or print any or all of these books, free of charge. These titles were scanned under the auspices of our Steven Spielberg Digital Yiddish Library, and have been made available online through the Internet Archive." See this Internet Archive page for more information on the project. Since the search box on that page yields results from all collections in the Internet Archive it is advisable to perform a search via the project page on the website of the National Yiddish Book Center itself. Books can be browsed by subject/keyword or searched for words in the title, year, author or publisher. They can be viewed online or downloaded in PDF or DjVu format.