What is "qanoon-e-islam"

Qanoon-e-Islam: or, the Customs of the Moosulmans of India is a book describing the culture and rituals of Indian Muslims in the nineteenth century. It was written by Jaffur Shurreef (Ja'far Sharīf) and translated into English by Gerhard Andreas Herklots in 1832. H. P. Lovecraft mentions this book in his story " The Case of Charles Dexter Ward", where its title has been used for disguising the text of the Necronomicon.