Peter R. Sonderby - formerly of Chicago, and most recently residing in Grand Beach, MI and Naples, FL, passed away peacefully on Wednesday, August 17, 2016, after a year-long struggle with cancer. He was 75 years old.

Peter is survived by his beloved wife of 26 years the Honorable Susan Pierson Sonderby (Ret.) of Grand Beach, MI and Naples, FL; daughter Kathleen (Richard Ross) Sonderby of Mill Valley, CA, son Christopher (Jill) Sonderby of Menlo Park, CA, and daughter Jennifer (Seth Blacher) Sonderby of San Francisco, CA; grandchildren Eliza, Lauren and Graham Ross, Max and Madeline Sonderby and Ari and Leo Blacher; brother Michael (Pam) Sonderby of Naples, FL; sister-in-law Tina Sonderby of Long Beach, IN; and nieces and nephews Brett (Lisa) Sonderby, Amy (Jeff) Kontir, Max (Glaucia) Sonderby, Elizabeth Sonderby and Robert (Carol) Sonderby. Peter was preceded in death by his parents, Max E. and Mary E. (Sjostrom) Sonderby, and his brother Stephen Sonderby.

Peter was born April 24, 1941 in Chicago. After becoming an Eagle Scout and earning his diploma from Morgan Park High School, Peter graduated from the University of Illinois (B.A., 1964) and the University of Illinois Law School (J.D. 1967), where he was an editor of the law review and Order of the Coif. Peter had a long and distinguished career as a litigator, arbitrator and mediator, focusing on complex commercial and securities cases. Peter was a partner at Chadwell & Kayser (1967-87) and Keck Mahin & Cate (1988-1994), principal at his own law firm, and most recently Of Counsel to Ulmer & Berne, LLP.

Peter regularly served as an arbitrator on panels of the National Association of Securities Dealers, National Futures Association, and American Arbitration Association. In addition, Peter served as President of the Northern District of Illinois Court History Association, Treasurer and Board member of the Lawyer's Club of Chicago, Board member of the Federal Bar Association of Chicago, and President of the Nordic Law Club. Peter received the 2012 Award for Excellence in Pro Bono and Public Interest Service for the Northern District of Illinois and was recognized on numerous occasions as a "Super Lawyer" by the Illinois Super Lawyers' Publication and Chicago Magazine.

In 2012, Peter retired to travel the world with Susan and enjoy time with family and friends.

Services have been held.