once-a-polecat:

Proper reading order for The Locked Tomb series:

1. Gideon the Ninth.
2. Reread Gideon the Ninth now that you know that redacted is redacted.
3. Harrow the Ninth
4. Reread Harrow the Ninth because you’re not entirely sure what the hell just happened. (Repeat if necessary.)
5. Reread Gideon the Ninth now that you know that redacted and redacted are redacted’s redacted.
6. Reread Harrow the Ninth while you wait for Nona the Ninth to come out.