Andy Liu, since 1980 a distinguished professor of mathematics at the University of Alberta, Edmonton, Canada, is one of the world's leading experts in problem solving. He is also noted for what has been called a “unique ability to present difficult concepts in a clear and logical manner”. His extremely bright young pupils, of both genders, are constantly winning prizes in tough mathematics competitions.

Andy has won many awards, the most recent being the 2003 Adrien Pouliot Award from the Canadian Mathematical Society for his contribution to Canadian mathematics education, and the 2004 Deborah and Franklin Tepper Haimo Award from the Mathematical Association of America for his excellence in mathematics teaching. He has edited a Book Review column for Crux Mathematicorum and a Problem Corner for Math Horizons.

Andy has finally drawn upon his vast experience as a teacher of elementary mathematics to produce the textbook you now hold—a book that covers everything a talented student would want to know about arithmetic. The book's wealth of stimulating problems starts with divisibility tests—simple rules for every integer up to 12, except 7—to a final chapter on numeration systems. Along the way are topics not usually found in such textbooks, such as the chapter on Diophantine Equations. Every problem is clearly stated, and every answer and every proof easy to understand.

Andy is a great believer in using recreational mathematics to trigger a student's interest. An admirer of mathematician/author Lewis Carroll, Andy sprinkled his book liberally with characters from Alice in Wonderland and Through the Looking Glass, especially in amusing dialogues between Alice and the Tweedle twins.

Arithmetical Wonderland is a book every teacher of the elementary grades should read and have on hand. Congratulations, friend Andy, for a difficult task well done!