This paper investigated and described four early Croatian children's encyclopedias which were published in the period from 1929 to 1962, and about which is spoken very little or almost nothing in the context of children's literature, although they are very significant. Children's encyclopaedias of that time have been released with the aim of having children and young people entertained by showing them the world around them, but also they were learning from them somewhat. It was shown who contributed to their creation, published them and with what purpose. The research has shown and explained their similarities and differences that are conditioned by the time they are published. Likewise, the proportion of images and text in their articles is shown and the affiliation of articles in a particular scientific or artistic area. The types of illustrations that appear in the encyclopaedias and the way children and young people have shown written are described. Knjiga za tebe, which dates back to 1930, is the first Croatian children's encyclopaedia and the work of Croatian authors intended for Croatian children and youth. A year earlier, in the Kingdom of Yugoslavia, albums with the pictures Svjetska čudesa are released, which, because of the variety of content and visual equipment, are considered encyclopedias but are work foreign authors and are not intended directly for Croatian children and youth. At the time of the Independent State of Croatia, or from 1942 to 1944, three volumes of the encyclopaedia's collection of Znanje i radost that are richly equipped with color, copper, and various drawings and photographs are published. In 1960 and 1962, two volumes of the encyclopedia for children and youth were published Svijet oko nas, whose content focuses more on the development of technology and new world achievements.