Finally, the collection included practical knowledge. Drawing lessons, music theory, and introductions to famous painters (Velázquez, Goya, Picasso) were included. There were also sections on manual trades—carpentry, gardening, and cooking—encouraging hands-on learning.

The collection included abridged versions of classics like Don Quixote, The Iliad, and Robinson Crusoe, as well as original poems and short stories written specifically to instill moral values such as courage, honesty, and perseverance.

Parents and children often read these books together. On rainy afternoons, families would gather around the table, flipping through pages of dinosaurs or distant lands. This created a shared cultural experience. Many adults today recall that their parents learned as much from the collection as they did.

In mid-20th-century Spanish-speaking countries, books were expensive luxuries. Sopena created a payment plan (often sold door-to-door by traveling salesmen), allowing middle-class and even working-class families to acquire the set. An entire generation gained access to knowledge that was previously reserved for elite private schools.