Dr. Mohamed O. El-Doma received his M.Sc. in Mathematics from Texas A & M University in 1982 and his Ph.D in Mathematics from Claremont Graduate School in California in 1986. For a year he visited University of Michigan-Dearborn, University of Tennessee at Knoxville, and, The American University of Beirut. And for a Summer he visited Cornell University, and, University of Potsdam, Germany. He also visited the Abdus Salam International Centre for Theoretical Physics (ICTP), Trieste, Italy, several times, and from ICTP he visited Universita di Trento, Italy, several times, and, also visited University of Tubingen, Germany. His research interests include age-structured epidemic diseases models, age-structured population dynamics models, and size-structured population dynamics models. He is elected as Vice-President for East Africa in the Executive Board of the African Mathematical Union (AMU). He is also a member of Editorial Board of 4 international journals, and a reviewer for Mathematical Reviews and Zentralblatt MATH.