This page contains spoilers. Read at your own peril!
The Golden Envelopes within the story of Paper Lily are the instructions to undertake rituals which actually work, they are first introduced in Project Kat where Kat gets her hands on one and finally finds a ritual which actually works, this may imply that the only rituals which work in the world of Paper Lily are those from the Golden Envelopes. Adding to this Lacie has to order her ritual online where it them arrives in her mail.
The likely use of rituals in the story is that of collecting souls, many books and a couple characters (within the facility found in dead end 4) make reference to this fact with most of it coming from the Library found with the repaired doorknob fragments. Within this Library it is revealed that the rituals are in fact a way for demons to collect souls for them to feed on and the Glen is likely in charge of whatever organisation in putting out the ritual letters (this organisation is almost assuredly The Council).
Many of these letters can be found in Project Kat once Kat finishes her ritual and begins interacting with the world her ritual takes her to, the letters made reference to in Project Kat refer to the following rituals:
| The Mirror Ritual |
| The Ritual of the Well |
| The Bus Ritual - The ritual Lacie used to get to the forest. |
| The Three-Room Ritual -The ritual Kat uses to enter the hallway of doors. |