The first Escher print I saw was the lithograph High and Low which decorated the wall of a class room where I taught mathematics. I studied it many times when my pupils were quietly working on problems that I had given them.

Many questions arose about the why and how of this print and the only one who could give the answer was the artist himself.

It so happened that I had a friend in Baarn that I helped to publish a book about mathematics. During one of my visits  to him the conversation turned  to  the Escher print High and Low, and my curiosity about the construction of this print.

Then he told me that Escher was his neighbour and that he was a kind man who would surely answer my questions. So I wrote a letter to Mr. M.C. Escher. He answered promptly that it was too cumbersome to answer my questions in a letter and he invited me over for a personal conversation. This first meeting (in 1956) was a wonderful experience: so many prints......so many stories! It was the beginning of a life-long friendship.

At this time Escher was putting the finishing touches on Print Gallery and I criticised the ugly cross in the upper left-hand corner.

When I got home, I wrote to him suggesting that he might be able to camouflage the cross by letting a clematis climb up it.

Just imagine how cheeky this was!

...Escher was almost sixty and had more than earned his stripes as a graphic artist and enjoyed considerable rcognition as the creator of very unusual prints....I was thirty and a teacher of mathematics, who had seen only a glimpse of what Escher had created in more than forty years as an artist.

Nevertheless some days later Escher wrote to me:

"....the clematis border along the "beams "of my Print Gallery would doubtless be beautiful. But those beams are meant to represent window frames. Furthermore I had probably already spent so much energy in thinking out the details of this image that I was too numb to be able to better meet aesthetic requirements. I simply have to rack my brains to produce these prints.

Besides, no print was ever made for the primary purpose of creating "something beautiful". That is also the reason that I never quite feel in the right place while I am among my fellow graphic artists. They strive for "beauty" first and foremost (even though this concept has changed greatly since the 17-th century --  for them as well), while I, on the other hand, focus maybe exclusively on the element of wonder, and therefore I also try to evoke only a sense of wonder in my viewers...."

This is eloquent not only because it expresses his own view of his work as an artist but especially because it shows how seriously he took the criticism of a young man who hardly knew his work.

In a long letter to his son Arthur about my first visit, he did not have had not even one word of condemnation of my behaviour:

"This time I want to tell you something about...a strange guy who suddenly one day decided to write me that my prints fascinated him, as well as the boys he teaches, and that he would like to come to Baarn to take a look. And so he did.

(In fact Escher had invited me !)....

...He was very interested in my jokes on perspective, and especially in my inversion print Convex and Concave as well in my regular divisions of the plane............etc."

After my first contact with Escher, I visited him regularly in his studio, and we wrote each other a lot of letters.  I had started a mathematical periodical for high school students (named Pythagoras that still exists), in which I wrote many articles about Escher prints. Regularly I asked Escher for permission to reproduce a print in poster format as a present for the subscribers. At that time we had more than 30 000 subscribers so that his work became well known in the Netherlands among high school students who were interested in mathematics.

In 1969, the last year that Escher lived in Baarn, I proposed to him that we record in a book how he began to develop his artistic output. "Once you are no longer with us (death was an ordinary subject of conversation), people will find all kinds of mysterious reasons for it" was how I put it to him.

Escher thought it was a good idea, and during the last few years of his life, I visited him every Sunday to gather information. It was a great help to me that Escher still had all the sketches for his prints and he generously proposed that I should take them to my home to study them further. So for some months I had hundreds of Escher drawings in my house.

With the help of his diaries, notebooks, sketches, and reproductions of all his prints I tried to chart Escher's oeuvre. One wall of my study was covered with reproductions and photographs of his prints in chronological order. Making up an inventory gave me insight into how Escher's interest advanced over time.

- Bruno Ernst, September 2005. Reproduced here with the special permission of Hans deRijk.