Architect Willem Reitsema Tzn (1885-1963) from Leens designed in the 1920s and 1930s and after World War II a large number of buildings in the north of the province of Groningen, on the Hogeland. Although varying in style from typical Amsterdam School and Nieuwe Bouwen, with influences of Wright and Dudok, to a more historicizing view, the buildings are all recognizable as designs by Reitsema. Especially in the rhythm of the details, of the brick building parts, the placement of the windows, the facade decorations and the expressive interiors, the hand of this musical architect can be recognized. No fewer than fifteen of his designs have now been designated as national monuments. This publication provides a visual overview of the life and work of this still relatively unknown architect, who unmistakably left his mark on the province of Groningen.