A selection of books from the Newberry's collection are now available digitally through the Internet Archive, according to the Newberry blog. Most are histories of religious congregations or specialized professional directories in Chicago.
The books are full-text searchable in a variety of formats.
Jewish resources include:
History of Kehillath Anshe Maarabh: Congregation of the Men of the West (1897)
The 50-year history of the oldest congregation in the city provides much information on the early Jewish community.
The Chicago Jewish Community Blue Book for 1918 is a veritable treasurehouse of names, photographs, history and commercial advertisements offering a good flavor of the times - it was published in 1918. Institutions and organizations are detailed, and there is an extensive listing of Chicago's Jewish residents, including addresses.
There are other non-Jewish resources listed, as well as early 20th century medical, law and real estate directories. Visit the link above for more information.