I have a question about the initiation process,
A Magus not initiated to the outer mystery of a House learn the lore ability of that House from an another Magus or from a text.
Then can that Magus try to initiate himself in the mysteries of the House (perhaps with the help of an Initiation Script)?
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I can't claim to actually know the answer to this question, and perhaps no one can before the Mysteries Revised edition is for sale.
But it seems to me that the initiations are handled like initiations to any other mystery. And I can't find any special rules regarding outer mysteries compared to ordinary ones. So that leaves us with the summary at page 4 and 5, and it does indeed state that the mystagogue can initiate himself.
But then again this feels a bit like reading a book with half the pages torn out. We might well be missing something.
You are correct.
You can self initiate...it just makes it harder to do...
How you gain the Outer Mystery of each House is detailled in that House's chapter. The Criamon one is, IMO, the simplest.
Can you self-initiate in Criamon? Sure, but if you don't join the ccommunity of the enlightened that the House represents you have the capping problems of the Gorgiastics.
You know, that sounded like a bowel complaint... until I realised there was an "r" missing.
Technically yes - as a more general example, if you find an ancient text from a lost Cult, and study it, then you can try to Initiate yourself using their scripts.
This may be difficult, as the script may likely require the Mystagogue to know the Virtue taught - and you won't know it, so you must Vary the script, or even Experiment. (See TMRE)
Self-Initiation is simply an Initiation where Mystagogue and Initiate as the same person (no problem!) but typically the Mystagogue lacks the Virtue being taught (otherwise why does the self Initiate want the Initiation?!)
Cult Lore is not particularly special - it's just the collection of quirky rites & rituals that help make up a Cult, and which help make Initiation Scripts work. (Add Cult Lore + Presence)
Correct! Unlike 4e Mysteries, TMRE (and its "sequel" HoH:MC) do not distinguish "Outer Mysteries" as anything peculiar or special... There amy be a cultural thing, that the members of the cult organization insist that everyone follow a certain path, starting here...but the mechanics don't force it.
And yes, the "book" has half its pages torn out, and you need to start by reading TMRE - out Real Soon Now!
promises, promises... 
"Promises, Pomises" came out ages ago - I ran it so many times I think my brain nearly leted
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