The things one finds on http://www.archive.org/ are absolutely amazing. I'm reading partrs of the 1892 edition of A Practical Treatise Upon the Jurisdiction of, and Practice in, the County and Probate Courtsof Illinois, Embracing A Collation of Statutes and Authorities Upon the Settlement of Estates of Deceased Persons; Correlative Relations of Guardian and Ward; ...."
by William Jones and Joseph Cunningham, Chicago, T. H. Flood, 1892.
Lots to learn in there for the genealogist and lots that makes sense once one reads it.
There will undoubtedly be references to this book in upcoming issues of Casefile Clues.