Why do I sometimes see the authors name written as “Giovannino” Guareschi?
Because that was his real name! “Giovannino,” is usually a diminutive of “Giovanni” (in English, the two names would be “Johnny” and “John,” respectively), so it’s not surprising that many people simply assumed that the name on “Nino” Guareschi’s birth certificate must be the more formal “Giovanni.” Included among those who got it wrong were the author’s publishers, and that’s why the name on your edition’s dust jacket may read “Giovanni Guareschi.” The publishers were made aware of their error and eventually switched to using “Giovannino” in Italy and much of Europe, but no move was ever made to correct things for the English-speaking audience (for fear of confusing loyal readers and losing sales, I suppose).