ProQuest Dissertations & Theses has abstracts of more than 2 million theses and dissertations submitted since 1743, including dissertations and theses from the University of Chicago. Dissertations published since 1997 are available in PDF format.
The most comprehensive bibliography of law school JSD dissertations and LL.M. theses is the Index to Law School Theses and Dissertations, by Sanford R. Silverburg (D'Angelo Law Library, Reserve Room, XXKF1.S552). This CD-ROM, published by W.S. Hein, was updated annually through 2006, but has not been updated since.
Many recent dissertations can be downloaded from ProQuest Dissertations & Theses. Dissertations not available from ProQuest can can sometimes be borrowed through Interlibrary Loan, or you may be able to order a copy at a discounted price.