"I Maestri Del Colore" series by Fratelli Fabbri Editori.
* It contains copyright information ("PROPRIETA LETTERARIA E ARTISTICA RISERVATA Copyright 1965 by Fratelli Fabbri Editori - Milano").
* It lists the publisher ("Fratelli Fabbri Editori").
* It mentions "Printed in Italy".
* It identifies individuals in editorial roles:
* DIRETTORE RESPONSABILE: DINO FABBRI
* CONDIRETTORE: FRANCO RUSSOLI
* ASSISTENTE: RENATA NEGRI
* The text at the top, "la più grande collana d'arte del mondo" (the largest art collection in the world), suggests this is part of a series of art publications.
* The mention of "I Maestri Del Colore" in your initial description confirms this is likely from a volume in the "I Maestri Del Colore" (The Masters of Color) series published by Fratelli Fabbri Editori.