The one-volume Propædia is the first of three parts of the 15th edition of `` Encyclopædia Britannica '' , the other two being the 12-volume `` Micropædia '' and the 17-volume `` Macropædia '' .
The Propædia is the first of three parts of the Encyclopaedia Britannica , the other two being the 12-volume `` Micropædia '' and the 17-volume `` Macropædia '' .