Sommer, William A., of O'Fallon, Missouri, died on Wednesday, December 21, 2011 at the age of 83. Dear son of the late Felix M. and Mary W. Sommer; devoted father of Kathleen M. Sommer, Dennis W. Sommer, Edward J. (Karen) Sommer, Paul M. (Susan) Sommer, Michael J. (Deborah) Sommer, Veronica A. (William) Mirgain, Mary Jo R. (Reid) Milster, and Gerard A. (Christen) Sommer; cherished grandfather of 10, step-grandfather of 2, great-grandfather of 13 and step great-grandfather of 5; dear brother of Jim (Mary Ann) Sommer, Martha LaBarge, Vincent Sommer, and Magdalyn (Gordan) Carmichael. He is preceded in death by one son, Gary A. Sommer, one grandson Joshua P. Sommer, and sister Theresa M. Sommer. Memorials may be made to donor's choice.