In 1968 Friso illustrated the bookcover for the Dutch translation of Jay William’s Tomorrow’s Fire – De Koningskruistocht.
The writer was so enthusiastic about the cover, that he asked Friso to make the illustrations for his next book, The Practical Princess.
With these illustrations Friso won the Golden Apple (Pomme d’or) at the Biennale d’illustrations in Bratislava in 1969.
The coorporation with Jay Williams led to many picture books.
The Practical Princess (1969)
School for Sillies (1969)
Stupid Marco (1970)
The Silver Whistle (1971)
Seven at one Blow (1972)
The Youngest Captain (1972)
Forgetful Fred (1974)
The Wicked Tricks of Tyl Uilenspiegel (1978)