GIOVANNI DORE is Associate Professor of Mathematical Analysis at the University of Bologna, Italy. He is the author of several professional papers on differential equations in Banach spaces and interpolation theory, among other subjects. Dr. Dore received the Lau- rea (1978) in mathematics from the University of Bologna. ANGELO FAVINI is Professor of Mathematical Analysis at the University of Bologna, Italy. His research interests focus on functional analysis, operator theory, differential equations in Banach spaces, and degenerate differential equations. He received the Laurea (1969) in mathematics from the University of Bologna. ENRICO OBRECHT is Professor of Mathematical Analysis at the University of Bologna, Italy. Dr. Obrecht’s research emphasizes boundary value problems for elliptic and parabolic partial differential equations and differential equations in Banach spaces, particularly for orders greater than one. He received the Laurea (1971) in mathematics from the University of Bologna. ALBERTO VENNI is Associate Professor of Mathematical Analysis at the University of Bologna, Italy. His research interests involve functional analysis, operator theory, and dif¬ferential equations in Banach spaces. Dr. Venni received the Laurea (1973) in mathematics from the University of Bologna.