This book honours Helena Rasiowa, a respected mathematician who was known for her openness to new ideas, her strong sense of quality and a far-reaching view of the role of mathematics in computer science. Rasiowa was born in Vienna, Austria in 1917, but she and her Polish parents moved to Warsaw after Poland re-gained independence. During her student life, Rasiowa was inspired by Polish logicians. After WWII, she met Andrzej Mostowski and started working at the University of Warsaw, where she got her PhD under Mostowski’s guidance. She was Editor-in-Chief of the journal Fundamenta Informaticae from 1977 till her death in 1994. The authors of this volume have built on the intellectual heritage of Helena Rasiowa. They have all proven to be influential in the field and were therefore invited to contribute to this publication. Subjects covered here include: monadic second order logic; game solution, epistemic dynamics and fixed-point logics; forcing and type theory; graded beliefs and intentions; local computations; approximation spaces; dynamic mereotopology and a retrospective view of process specification formalism.