Sending books to inmates is banned in Diavata prison, where Nikos Maziotis is currently incarcerated. So, the comrade can only receive letters (at best some news reports, too). It is obligatory to indicate a sender address, otherwise letters are not delivered.
To write to the comrade:
Geniko Katastima Kratisis Thessalonikis
57008 Diavata, Thessaloniki, Greece
source: athens imc