This specific range of 21 core albums represents a pivotal era in the series' history, transitioning from the late 1960s into the early 1970s. During this period, the series moved toward a more standardized "Ligne claire" style as it was serialized in magazines like Tintin .
The inclusion of albums in a pack typically refers to special editions published outside the regular numbering. These often include: This specific range of 21 core albums represents
(March 1967) – A classic adventure that sets the tone for this era. This specific range of 21 core albums represents