This book is a product of love and respect. If that sounds rather odd I initially apologise
but let me explain why I use those words. The original manuscript was of course Freudenthal¿s
but his colleagues have carried the project through to its conclusion with love for the man
and his ideas and with a respect developed over years of communal effort. Their invitation to
me to write this Preface e- bles me to pay my respects to the great man although I am probably
incurring his wrath for writing a Preface for his book without his permission! I just hope he
understands the feelings of all colleagues engaged in this particular project. Hans Freudenthal
died on October 13th 1990 when this book project was well in hand. In fact he wrote to me in
April 1988 saying ¿I am thinking about a new book. I have got the sub-title (China Lectures)
though I still lack a title¿. I was astonished. He had retired in 1975 but of course he kept
working. Then in 1985 we had been helping him celebrate his 80th birthday and although I said
in an Editorial Statement in Educational Studies in Mathematics (ESM) at the time ¿we look
forward to him enjoying many more years of non-retirement¿ I did not expect to see another
lengthy manuscript.
