The Forbidden Annotations: Who Really Wrote in the Half-Blood Prince's Potions Textbook

Of all the artefacts to emerge from the turbulent years surrounding the Second Wizarding War, few have attracted as much scholarly attention as a single, battered copy of Libatius Borage's Advanced Potion-Making, edition unknown, found among the personal effects of a Hogwarts student in the mid-1990s.

The margins of this unremarkable textbook — standard-issue, water-stained, and missing its back cover — are filled with annotations so sophisticated that senior Potioneers at St Mungo's Hospital initially refused to believe a student had written them. Yet written by a student they were.

What the Annotations Reveal

The modifications fall into three distinct categories: corrections to Borage's original instructions, entirely new potion variants, and, most controversially, the seeds of spells that would later be formally classified by the Department of Mysteries.

• Brewing corrections: At least fourteen of Borage's standard instructions are crossed out and replaced with techniques that reduce brewing time by up to 40% while improving potency.
• New variants: Six completely original potions are outlined in the margins, two of which were independently discovered by professional Potioneers decades later.
• Spell notation: Three incantations are scrawled between chapters, in a different ink, suggesting they were added over time rather than in a single sitting.

The mind that wrote these notes was not experimenting. It was correcting. Whoever this was, they already knew the answers before they picked up the quill.

The Question of Authorship

The inscription on the inside cover — 'This book is the property of the Half-Blood Prince' — is written in a hand that matches the annotations throughout. Graphological analysis conducted by the Wizarding Forensics Institute in Edinburgh confirms the annotations were made by a single author over a period of at least five years.

Cross-referencing the potion variants with published Ministry research from the 1970s suggests the author was active during that period — placing them at Hogwarts between approximately 1968 and 1975. This window, frustratingly, covers thousands of potential students.

Why It Still Matters

Beyond the historical mystery, the annotations represent a genuine contribution to Potions as a discipline. Several methods described in the margins have been quietly incorporated into the current Hogwarts curriculum without attribution, a fact that has prompted renewed calls from the academic community for proper scholarly credit to be given.

Whether the Half-Blood Prince is remembered as a cautionary tale or a misunderstood genius may ultimately depend on who controls the narrative — and who gets to decide which annotations are worth preserving.