Canon and Heresy
Translation and Mysticism
I'll discuss the first now; the second is a bit longer and trickier.
Canonization isn't as much a process of definig what's 'in' as defining what's 'out'. Admittedly, there are different types of canons (normative, formative, curricular). Canon (formative) defines the shared beliefs, values, practices, and interpretations of a community. Thus, whatever presents an alternative is heresy. Declaring books to be apocryphal means that to accord them religious status is heretical (see Minshna Sanhedrin 10:1 - I read' ha-korei be-sefarim chitzoni'im' to mean that one who reads from an apocryphal work AS ONE WOULD READ FROM THE TORAH then one has cut himself off from the Jewish (i.e. Rabbinic) community. The Mishna couldn't give a darn about reading Harry Potter or even the New Testament for leisure (though it's anacronistic to talk of reding for leisure, reading from a scroll was not the norm - it was still an oral culture).
Thus, creating a canon defines who is a heretic, and is often done for the PURPOSE of defining who is a heretic. The flip-side is that a heretic is one who doesn't recognize the exclusivity of the normative (i.e. legal) or formative status of the canonized document.
There are also layers of canonicity. There were many groups who accepted the canonicity of the 5 Books of Moses, but not the Prophets. Or the Prophets but a different set of Hagiographic writings (Ketuvim), or the full Tanach but not the Babylonian Talmud (as normative canon), and so forth. Even today, acceptance of certain works as 'canonic' in the normative (e.g. Mishna Berurah) or curricular (e.g. the secret shiurim of the Brisker Rav) will define a person as being 'in' or 'out' of a particular community. It's small scale. but of the same phenomenon.
Acamo"l. Stay tuned for more useful tautologies.