There does seem to be some confusion here, and it is with some trepidation I comment my research seems to contradict many well known experts....
My understanding is that the first edition was printed in 1965, as evidenced by this ad.... https://www.ebay.it/itm/143217913575
There is no indiction that it is the first edition because no-one would know if a subsequent edition would appear.
I like Skiwalk have second edition - as previous post. This clearly states that - "Finito di stampare nel gennaio 1966" - which according to google translate - "Finished printing in January 1966". I conclude the 2 edition followed on very quickly from the first, seemingly months!
My second copy, the well documented type with Fusi's "signature" has "Terza Edizione , Third Edition" printed together with "Copyright C 1978".
So I am unclear how a 1974 one is a so-called 'second edition', could someone with a copy please post details?
Just to clear up a long ago posting about cost and printing, viz Prezzo L. 8.000 = Lira 8,000, this still causes me confusion because the 'dot' is still used in Italy with Euro....the simple explanation is that Italians swap over the use of the dot and comma! Others use the comma to denote thousands, Italian the dot, and we use the dot to differentiate between whole pounds and any pence. In Italy E1.234,56 elsewhere E1,234.56