- Ph.D. Harvard University, 1964
- M.A. Harvard University, 1961
- B.S. Polytechnic Institute of Brooklyn, 1960

- University of Wisconsin, Professor Emeritus of Mathematics, 2011-present
- University of Wisconsin, Richard Brauer Professor of Mathematics, 1995-2011
- University of Wisconsin, Professor of Mathematics, 1971-1995
- University of Wisconsin, Associate Professor, 1969-1971
- Yale University, Assistant Professor, 1966-1969
- U.C.L.A., Assistant Professor, 1964-1966

- IDA/CCR, LaJolla, Mathematician, 2004
- University of Warwick, Visiting Fellow, 1976-1977
- U.C.L.A., Visiting Professor, 1972-1973
- IDA/CRD, Princeton, Mathematician, 1969-1970

- Member of the inaugural class of Fellows of the American Mathematical Society, 2012
- Deborah and Franklin Tepper Haimo Award for Distinguished University Teaching, MAA, January 2000
- Award for Distinguished University Teaching, MAA Wisconsin, 1999
- Underkofler Excellence in Teaching Award, 1998
- Houses Professorship, 1995-present
- Plenary speaker, Canadian Math Soc. summer meeting, Windsor Ontario, June 1989
- Main lecturer, CBMS Conference, Mankato State University, June 1985
- Invited speaker, American Math Society meeting, Washington D.C., October 1979
- Invited speaker, 29th British Mathematical Colloquium, University of Edinburgh, 1977
- Lester R. Ford Award for "What is a group ring?", 1976
- Romnes Faculty Fellowship, 1975-1980

- Virtual talk, Centenary Conference, Aligarh Muslim University, India, March 2021
- Virtual talk, Group Theory Conference, Ischia, Italy, December 2020
- Group Rings, Groups and Rings, in honor of Jairo Goncalves, Univ. of Sao Paulo, Brazil, September 2-5, 2019
- AMS meeting in honor of Lance Small, UC Riverside, November 4-6, 2017
- Algebra Extravaganza in honor of Ellen Kirkman and Martin Lorenz, Temple University, July 24-28, 2017
- Algebra Conference in honor of Louis Rowen, Tel Aviv, Israel, June 26-30, 2017
- Groups, Rings and the Yang-Baxter Equation, Spa, Belgium, June 19-23, 2017
- Groups, Rings and Group Rings Conference, Edmonton, July 11-15, 2011
- Midwest Ring Theory Conference in honor of John Beachy and Bill Blair, Northern Illinois, September, 2010
- Noncommutative Algebra Conference in honor of Mia Cohen, Sde-Boker, Israel, May 24-27, 2010
- Atlantic Algebra Centre, St. John's, Newfoundland, March, 2010, announcement
- Conference on Character Theory of Finite Groups in honor of Marty Isaacs, (organizer), Valencia, June, 2009
- Algebraic Groups Conference in honor of A. E. Zalesskii, Milan, May, 2009
- Hopf Algebra meeting in honor of Susan Montgomery, U.S.C., February, 2009
- Conference on Noncommutative Rings in honor of S. K. Jain, Univ. of Ohio, June, 2008
- Conference on Noncommutative Rings, Alden-Biesen, Belgium, September 2-5, 2007
- Antalya Days in honor of Brian Hartley, Antalya, Turkey, May 23-27, 2007
- Conference on Non-Commutative Rings, Chennai, India, December 18-22, 2006
- Conference on Noncommutative Algebra in honor of Lance Small, UCSD, February 18-20, 2006
- IMMERSE talks, University of Nebraska, July 2005
- Conference on Algebra and Applications, Ohio University, March 2005
- AMS Special Session on Ring Theory, N. Carolina State, October 2003
- AMS Special Session on Infinite Groups, SUNY Binghamton, October 2003
- Ring Theory Conference, Univ. of Warwick, England, September 2003
- Around Group Rings, Jasper, Canada, February 2002
- Midwest Lie Theory Conference, DePaul University, October 2001
- Group Rings Conference, Bialystok, Poland, June 2001
- CMS Conference on Ring Theory, St. John's, Newfoundland, May 1999
- Groups and Group Algebra Meeting, Wisla, Poland, June 1998
- Kurosh Algebra Conference, Moscow, Russia, May 1998
- Ring Theory Conference, Trento, Italy, May 1997
- Group Algebra Meeting, Kananaskis, Canada, February 1997
- Ring Theory Conference, Miskolc, Hungary, July 1996
- Martindale Retirement Conference, U. C. Northridge, October 1995
- Aneis de Grupo, Universidade de Sao Paulo, Brazil, August 1995
- Coloquio Brasileiro de Matematica, Rio de Janeiro, Brazil, July 1995
- Algebra-Symposium, University of Essen, Essen, Germany, July 1995
- Escola de Algebra, Unicamp, Campinas, Brazil, July 1994
- Contact Franco-Belge en Algebre VI, Diepenbeek, Belgium, June 1993
- CBMS Hopf Algebra Conference, DePaul Univ., August 1992
- LMS Symposium on Non-Commutative Rings, Durham, England, July 1992
- Bad Honef Conference, Germany, June 1990
- Azumaya Retirement Conference, Indiana Univ., May 1990
- Mid-Atlantic Algebra Conference, George Mason Univ., October 1989
- Microprogram on Noncommutative Rings, MSRI, July 1989
- Amitsur Retirement Conference, Bar Ilan Univ., Israel, January 1989
- Conference on Hopf Algebras, Beer Sheva, Israel, January 1989
- Midwest Ring Theory Conference, DeKalb, May 1988
- Midwest Ring Theory Seminar, Wayne State Univ., November 1987
- Special Session on Ring Theory, AMS meeting, Salt Lake City, 1987
- 77th Ontario Mathematics Meeting, Trent University, October 1986
- Oberwolfach Conference, Oberwolfach, Germany, April 1986
- "Algebra Day" at University of Ottawa, April 1985
- St. Andrews Colloquium, Edinburgh Math. Soc., July-August 1984
- Conference on Group Actions, Bowdoin, July 1984
- NATO Ring Theory Conference at Antwerp, August 1983
- Midwest Ring Theory Conference at Michigan State, October 1982
- Southern California Algebra Conference at U.C.L.A., January 1982
- Distinguished Lecturer Series, University of Southern California, January 1982
- Distinguished Lecturer Series, University of California at Santa Barbara, 1981
- Midwest Ring Theory Seminar at Northern Illinois, 1980
- Special Session on Infinite Groups, AMS meeting, Philadelphia, 1980
- Ohio Ring Theory Conference, April 1979
- Distinguished Lecturer Series at University of Texas at Austin, November, 1978
- Conference on Group Rings, University of Alberta, June 1978
- Conference on Group Algebras, University of Essen, May 1978
- Warwick Algebra Weekend, University of Warwick, April 1978
- AMS meeting, Special Session on Ring Theory, Columbus Ohio, March 1978
- Oberwolfach Conference, Oberwolfach,Germany, May 1977
- Scottish Algebra Seminar, April 1977
- Ring Theory Conference, Ohio University, April 1976
- Twelfth "Algebra Day" at Carleton University, Ottawa, Canada, 1975
- Applications of Ring Theory to Group Theory, AMS meeting, St. Louis, 1974
- Group Representations Symp., Instituto Nazionale di Alta Matematica, Rome, 1972
- Southern California Algebra Conference at Cal Tech, 1972
- Symposium on Algebra, University of Kentucky, May 1970
- Group Representations Conference, University of Wisconsin, Madison, April 1970

- Cambridge University
- Oxford University
- Queen Mary College
- University of Leeds
- University of Aberdeen
- University of Stirling
- Bedford College London
- Royal Holloway University of London
- University of Sheffield
- University of Birmingham
- University of Bristol
- University of East Anglia
- University of Leicester
- University of Essen
- University of Antwerp
- Catholic University Leuvan
- University of Alberta
- University of Manitoba
- Memorial University Newfoundland
- Dalhousie University
- University of Waterloo
- University of Chicago
- Michigan State University
- Notre Dame University
- University of Illinois
- Northwestern University
- University of Wisconsin-Madison
- University of Wisconsin-Parkside
- Texas A & M
- Texas Tech
- University of Texas-Austin
- University of Kentucky
- University of Cincinnati
- Brooklyn Polytechnic Institute
- Virginia Polytechnic Institute
- California Institute of Technology
- Claremont College
- University of California-Los Angeles
- University of California-Irvine
- University of Southern California
- California State University-Los Angeles
- SUNY-Binghamton
- Ohio State University
- University of Liverpool
- Syracuse University
- McMaster University
- University of Mainz
- Wayne State University
- Beijing Normal University
- Peking University
- Hebei Normal University
- Jilin University
- Shanghai Normal University
- Vassar College
- Oberlin College
- Temple University
- University of Iowa
- Federal University Rio Grande do Sol
- University of Sao Paulo
- University of Brazilia
- University of Paris
- University of Palermo

- Editor, Algebras and Representation Theory, 2001-2011
- Editor, Journal of Algebra and its Applications, 2001-2016
- Editor, Sao Paulo J. of Mathematical Sciences, 1995-2013
- Editor, Journal of Egyptian Math. Soc. 1994-2013
- Editor, Beitrage zur Algebra und Geometrie, 1993-2013
- Editor, Proceedings Edinburgh Math. Soc., 1992-1995
- Editor, International J. of Mathematics, Game Theory and Algebra, 1991-2013
- Represented CBMS at Formanek Conference, July 1990
- Member, Committee on NSA grants, 1990-1992
- Editor, Proceedings, Royal Society of Edinburgh, 1989-1998
- Member, Council of AMS, 1984-1988
- Editor, Proceedings AMS, 1981-1988
- Editor, Communications in Algebra, 1976-1985
- Editor, Journal of Indian Math. Soc., 1986-2013
- AMS Special Session on "Group Rings", Washington D.C., October 1979
- Editor, Pitman Publishing Co., 1977
- Editor, Marcel Dekker Co., 1972-2005
- Reviewer for Math Reviews until 2017
- Referee for numerous journals

- Charles Hampton (1972)
- William Chin (1986)
- Declan Quinn (1986)
- Clem Jeske (1989)
- Charles Welsh (1990)
- Scott Lanning (1994)
- Will Temple (1994)
- Mark Wilson (1995)
- Stefan Catoiu (1997)
- Darren Parker (1998)
- Chia-Hsin Liu (1999)
- Antonio Behn (2000)
- Mustafa Elashiry (2010)