Who would have made and used it?

The book is a regimen of baths and health for a court or spa physician, in the tradition of Pietro da Eboli's De balneis Puteolanis, with an herbal and a pharmacy attached.

The book is a compendium of women's medicine (conception, pregnancy, childbirth, bathing) in the Trotula tradition, kept private by its users.

The book is a natural-philosophical encyclopaedia of the scholastic kind, organised by domain (plants, heavens, waters, medicines), in a constructed or private notation (the v0.1 framing).

The book is an alchemical and distillation manual: plants as materials, jars and tubes as apparatus, baths as operations, recipes as procedures.

The book is the working compendium of a religious house's infirmary: simples, a bloodletting and bathing calendar, baths, the cosmos as a physician needs it, an apothecary's jars and an antidotary.

The book is an astrological-medical compendium organised on Picatrix-style planetary correspondences.