The La Pira archive has vast number of letters that La Pira sent to popes from Pius XII onwards.
The character of these letters is explained by La Pira himself in a message sent to Cardinal Angelo Dell’Acqua requesting him to pass on a letter to the Holy Father. These are … stages of a single meditation that is slowly occurring in my soul. This, it seems to me, is the fundamental line of history today! I you wish please deliver them, but only if you deem I will not annoy the Holy Father with these frequent letters. I write as a “debt of conscience” because I feel that by writing and expressing the “directives” of my meditation and my action of performing a specific duty.
The letters to Pius XII are published by the La Pira Foundation in the volume:
G. La Pira, Beatissimo Padre. Lettere a Pio XII, Andrea Riccardi & Isabella Piersanti eds., Milano, Mondadori 2004.
A volume containing the letters to John XXIII has been published in 2009:
G. La Pira, Il sogno di un tempo nuovo – Lettere a Giovanni XXIII, Andrea Riccardi & Augusto D’Angelo eds., Milan, Edizioni San Paolo, 2009
An anthology of the letters to Pope Paul Vi is currently under preparation.
Here you can read some abstracts of