Well goddamn. This volume sees the end of the rather gargantuan final Astro Boy story, which goes through so many ups and downs and phases that it's almost ridiculous. Somewhere along the line, what started as an "Astro goes back in time" story turns into essentially a "Year One" style expansion on his origin story. This gives the story a sort of cyclical, almost Buddhist nature (probably a fair assertion, given that one of Tezuka's most famous works is an epic reworking of Buddha's life) and leaves us not realizing, until the end, the real significance of a scene back in the last volume. That's really the most I can explain without great, great spoilers.
Basically, Tezuka details the "history" of the future he's created for Astro Boy--a future that obviously doesn't mesh with what has actually happened, but he probably knew that as his 1960's were already off too, so one should see it as an "alternate." Nonetheless, despite all the inaccuracies and cartoony jokes, it feels internally consistent. For example, the somewhat deus ex machina device for giving robots rights looks a bit contrived, but the after effects feel very, very real.
Emotionally, this entire story, from its start in Volume 6 to its ending here, is incredibly poignant, jumping back and forth from humor, action, and imaginative sci-fi to some stark emotional realities: it's definitely clear that Tezuka was only a year away from the start of his truly adult works. War, paranoia, civil rights, bigotry, and a terribly abusive father are all covered at length, but there's still always time for aliens, space fungus, gangsters, futuristic theme parks, and the rest. Also, unlike most Astro Boy stories, I found myself genuinely unsure of how the story would end up until the last panel. (Incidentally, it actually ended with a goofy pun that reached all the way back to the beginning of the story for its joke--deep down, I guess Tezuka always had his goofy side.)
There's one other short story in this volume after the end of that incredibly long one (because these storylines are all presented entirely out of order, for some reason) and it's a good one. But take a break before reading it, because it feels small and inconsequential when compared with what it follows.