This book contains the problems and solutions of the Youth Mathematical Olympiad named after Prof. Gillis, held in the years 1983-1996. In addition, the book contains the problems and solutions of the Israel-Hungary math competitions, held in 1990-1996. The book is dedicated to the memory of Prof. Gillis who died in 1993. Prof. Gillis was a great scientist and educator and was the living spirit in the world of mathematical competitions in Israel.

One of Professor Kleiner's main areas of interest is the history of mathematics and its use in teaching mathematics. Four of his articles in this field have been translated into Hebrew and appear in this collection. For the article "The Evolution of Group Theory - A Brief Survey" he received the Allendoerfer Prize from the Mathematical Association of America in 1986. In 1989, the same association awarded him the George Pólya Prize for his article "Evolution of the Function Concept: A Brief Survey". In 1991 he again won the Allendoerfer Prize, this time for "Rigor and Proof in Mathematics: A Historical Perspective". The reasons of the award committees appear verbatim before each article in this collection.

The first part of the book includes classic minimum and maximum problems, solved for decades by some of the world's greatest mathematicians. The second part presents general methods for solving minimum and maximum problems in the fields of variation mathematics, linear and non-linear planning, and more.