I'm sure he realizes it, but Harry literally obliviated everything in his memory, which would presumably include knowledge of any anti-obliviation counter measures (like the signals that were mentioned early on).

Unless there's some spell or artifact we haven't heard of before now that blocks/reverses Obliviation, I am going with it worked. And from a meta perspective, we know the story is winding down, so Voldie coming back with his full memory and then having another showdown with a different solution seems highly unlikely.

You can't say "everyone have lived" in British English, either. But number agreement in English is generally not to be taken entirely seriously, so "everyone has ... their life/lives" is fine in both variants. The reason is that "everyone" works semantically like "all people", not like "every person", but just happens to nonetheless trigger singular agreement on the verb. That's also why you can say "everyone liked each other", like "all people liked each other", but not "every person liked each other".

Has the 26-hour day been explained yet?

All of tomorrow's article will be about nailing down what scarcity is. Among other things, we shall see that everyone has lived with scarcity all their...lives? (Which is correct here, life or lives? Do not mean to be suggesting reincarnation.)

Will say right now for avoiding confusion that scarcity is being used as technical economics word, not implying deprivation or poverty.

That seems to be the only thing that makes sense, but does the text say that anywhere?

He is. But assuming that he is super-prepared, beyond the abilities and equipment we've seen or been given reason to postulate, results in an unsolvable puzzle. Someone as intelligent, experienced, prepared and resourceful as Voldemort could theoretically have a counter for anything we can come up with.

We know or can reasonably assume that he obtained a gun specifically as a solution to the problem of not being able to injure or kill Harry with magic. We don't have any reason to believe that he has prepared further, backup solutions to that specific problem.

One further remark on that last paragraph. "A potion spends that which is invested in the creation of its ingredients". What counts as creation? Ultimately, pretty much everything on earth is made of the remnants of supernovas...

Thanks for keeping me honest, but I don't have the book available to me now either. If you can quote from a different language edition (especially German), that would help.

Without the book to review, what I relied on in my comment[^1] was this: When I first read it, I came away with the impression that there was no secret. I remember reading about Petunia's letter and concluding that the Evanses knew all about Witches and Wizards. (The differing reactions to them are like the attitudes towards Mutants in Marvel comics.)

[^1]: That, and checking the Wikia for first mentions.

Perhaps, primed by this, I missed later references to secrecy. (But that doesn't help with any comments by McGonagall in the prologue.) I do remember being disappointed (but understanding) with the secrecy in book 2.

Regarding Azkaban: No mention in book 1, yes, but it is mentioned in book 2, before it started to play a major role in book 3.

Yes, certainly. In fact, I always thought that Hagrid's trip to Azkaban in book 2 was set up so that we'd know what the title of book 3 meant. (I knew that title before I read book 2.)

Even after re-reading the horcrux stuff a couple times, I'm still confused.

There are two types of horcuxes, v1 and v2. v1 only captures your mindstate as it was at the time of creation. v2 updates all horcruxes to the current mindstate. v1s were hidden in the canonical places (diadem, slytherian's locket, etc), v2 in the hard to reach ones (mariana trench, pioneer probe).

After 10/31/1981, Tom's mindstate bounced around the v2 horcruxes. In 1992, Quirrell found a v1 horcrux ("one of my earliest"). How does that work? How can a v1, which hasn't updated, give rise to the current Voldemort?

He wouldn't have Slytherin's monster's power, or knowledge of anything after the horcrux's creation.

Also, how are those current v2 backups handling two Toms? Which mindstate is getting backed up? Probably the QQ one, but how does V know the system even works??

And isn't it suspicious that Quirrell finds this horcrux just a few months before Harry is to attend Hogwarts?

Upon rereading 108, it's ambiguous if QMort is telling the full truth about horcruxes. His Parseltongue confirmation comes later, after his horcrux explication.

Harry is the viewpoint character, and he thinks everyone is an idiot except him and Quirrell. He is in error. He has been consistently in error about this since ... forever. It's probably a character flaw that he shares with Voldemort, although Harry has a somewhat less murderous form of it.

For instance, Harry believes that the wizarding economy should be trivially exploitable via exchange with the Muggle precious-metals market. He believes this because even though he knows about half-bloods (i.e. witches and wizards who have a Muggle parent), he thinks that he is special and that nobody else ever would have thought of that.

Similarly, he believes that he is the first to come up with the idea of combining magic and Muggle science. He isn't that, either. He doesn't realize this even after he is given the (ostensible) diary of Roger Bacon.

And here's the thing ... he doesn't update about these errors. He's not particularly curious about them. "Hey, wait, there are Muggleborns; what's the chance any of them has ever had a relative in Muggle banking, finance, or economics?" "Oh, Roger Bacon was a wizard? I had better learn me some Latin so I can find out what the history of magic/science interaction has been."