Erich Kästner's books from the 20's and 30's have lovely illustrations. We got some of them (Emil und die Detektive, for example) from our dear old neighbour, Herr Dr. Rosenplänter, when we lived in Germany.
The illustrator was Walter Trier. He had to flee Germany with his family in 1936, because he was Jewish. I think I have a crush on him (he looks a little like Falco).
Trier was a prominent illustrator, but he also provided caricatures and cartoons for Simplicissimus, covers for the British magazine Lilliput, Allied propaganda flyers to be thrown over Germany during the war. He was offered work by Disney, but refused - he wanted to work under his own name. Shortly after emigrating to Canada, he died in his atelier 1951.
A map of Europe in WW1
German boxer Max Schmeling
Hermann Göring paper doll "for the young"
Covers for Lilliput magazine (always with a man, a woman and a dog)
Some of Kästner's and Trier's books
Erich Kästner was forbidden from publishing in 1933, and his books were publicly burnt. He was hounded by the Gestapo, but he continued to write and publish his works in Switzerland, and he travelled to meet Trier in Austria in the 1930's. In 1943, he was no longer allowed to write, either. After the war, Kästner dealt with his experiences in pacifist books for children and adults. He continued to work together with his friend Trier.
You can follow Emil and the detectives' path through Berlin of 1929 in photos, drawings and maps here.