The term “Mudblood” (dirty blood) was used as a derogatory name for anyone who had one or both parents that were Muggles. Hermione Granger was muggle-born, and she was often called a “Mudblood” from other witches and wizards of pure lineage (though almost everyone could trace a muggle in their family history). The Mudblood book was one of the propaganda items that the Ministry of Magic produced in order to get other witches and wizards to steer clear from muggles.
Wizardry Workshop has the complete booklet in its normal size. I shrunk it down to make it an ornament.