The Standard Book of Spells, Grade 3 is a book written by Miranda Goshawk. As a required third year textbook, it can be bought at Flourish and Blotts for one galleon. It is the only Spellbook found in Harry Potter and the Prisoner of Azkaban so far, as well as the only book of spells which can be found in the trunk.
"The third instalment of the indispensable guide to your basic magical needs."
From the Story
"The Standard Book of Spells, Grade 3, by Miranda Goshawk, is the required text for third-year Hogwarts students."