Many people suffered the trauma of mathematics in their childhood. Today they may discover its beauty. In the book A Journey in Abstract Worlds , the reader is presented, in a light and humorous way, with some of the principles of abstract thinking, and then bridges are drawn between it and tangible thinking. The relationship between mathematics and visual art is illustrated through the mathematical analysis of symmetrical paintings. The book is intended for open-minded people of all ages. There is no need for mathematical education beyond basic knowledge. Those with humanistic and artistic tendencies will be able to benefit from it just as much as those with realist tendencies. It was written from the point of view that mathematics is not only a useful and theoretical science, but also an art form that can bring pleasure to a wider audience than is usually exposed to it.

This textbook covers the following topics: probability and combinatorics, functions, probability distribution, and random variables.

Semantic Truth Theories uses the techniques of mathematical logic to develop a new semantic treatment of the concept of truth based on ideas of Saul Kripke. Yael Cohen goes on to solve the Liar paradox, Hempel's raven paradox in the philosophy of science, and other classical problems of philosophy. She does this by enlarging the scope of formal logic to include concepts of presupposition besides the usual implication. The book thus provides a unified treatment of many topics having to do with truth, topics whose deep and unsuspected interconnections are not visible without the insights of mathematical knowledge which the author elaborates. The early chapters of the book contain an accessible introduction to semantic paradoxes which should be useful to students.

In 1931, Kurt Gdöel published a revolutionary article - an article that challenged some basic assumptions on which a significant part of the research in mathematics and logic was based until then. The unknown land Terra Incognita that he discovered is recognized today as one of the greatest contributions to the development of scientific thinking. This is the first book to present to the enlightened reader who is not an expert a readable explanation of the main ideas and extensive history of Gödel's Proof. It offers every cultured person, who has a sympathetic approach to logic and philosophy, an opportunity to satisfy the intellectual curiosity regarding the subject that has been blocked from him until now.

On the twelfth of February 1961, Abraham A. Fraenkel celebrated his seventieth birthday. For over half a century his books, papers and teaching have exerted great influence on the research in the foundations of set theory and the philosophy of mathematics. The essays in this collection are dedicated to Professor Fraenkel by the authors as a token of their respect and admiration.