The author of these books was Mr Alessandro Soriani, a teacher of Italian in Denmark.
As far as I know, there are two “Soriani” books, basic and advanced.
The advanced one has many pages with pictures, mostly sort of collages in an avantgarde style (they remember me of some work of the visual artists of “Gruppo 63”, like Pignotti or Ori).
There are many exercises with self-correcting schemes, which were quite used in the seventies. You had a question with two or three possible answers. If you hit the right one, you went forward, to the next question – if you hit a wrong one, according to the type of mistake, you were re-directed to a grammar explaination, or a conjugation chart, etc. and from there you could start again.
It is a “if…then goto…” scheme that you were going to find some years after in the basic programming, ervidently the computer revolution was in the air, but the hardware was still not available to the masses.