There are a number of things I like about Tomi Ungerer's work:
The strong sense of design, the way he flits about with his style (compare the Paris Review cover above with the xylophone cartoon below it) and, perhaps most of all, the subversive nature that runs through everything he does.
For example: That last image is scanned from 'No Kiss For Mother', Ungerer's 1973 children's book about a grumpy kitten who refuses to reciprocate his mother's affections. You'll see in this last image - in the background - that one of the cats is dressed up as an some kind of Nazi officer, with the Swastika on his arm being replaced by a question mark.
Very odd - and can you imagine that being allowed today?