Methuselah’s Children - from The Future History of Robert Heinlein Vol. II
Or, where it all began, Mark II.
Originally entitled While the Evil Days Come Not (and earlier parts of two story notes The Shadow of Death and Longevity) this is the first appearance of The Howard Families and Heinlein’s most recurring character, Lazarus Long aka Woodrow Wilson Smith aka Captain Aaron Sheffield.
It concerns the persecution of a group of people who have extended lifetimes.  Lazarus Long, for example, is over 200 years old at the time the story begins.  Once the short-lived know the Howards are out there they pursue them to discover their secret.
Interestingly, in MC there is no secret.  It’s genetics and a selective breeding program.  However, it wasn’t always that way.  According to the story notes, the original idea was that the long-lived got that way through positive thinking ‘visualizing’ themselves as healthier and younger.  THAT would have meant that there was a secret worth peeling out of them and taken the story in an all new direction.
However, John W. Campbell hated that idea.  According to the notes he said, “It was fishy and it stunk.”  Heinlein argued, Campbell stood firm and Heinlein responded to the demands of the customer and come up with the genetic explanation on the fly.  So the basis of the biggest, longest running concept of his writing career, The Howard Families and their long livespans, was a patchwork job to get Campbell to buy a story.  Excellent.
One of the interesting things about the story isn’t necessarily the space travel - in the story the Howard’s flee Earth in a stolen spacecraft.  Well and good.  But we also see, at the very highest levels, how the Covenant-based government that is held so highly in Coventry and Misfit is showing cracks.  The members of the Howard Families are protected by the covenant, sure, but not when the government thinks they’re withholding longevity information from the rest of the world.  Instead, with little thought, the covenant is placed aside and the members of the Howard Families are placed under arrest and even potentially torture to extract the secret.  When they state that there is no secret that’s brushed aside and the government redoubles its efforts against them.  In this, again, Heinlein notes that governments and social systems don’t remain static and that even systems that respect the rights of the individual eventually fall or grow corrupt or calcified.
This also features the first appearance, as mentioned, of Lazarus Long, a character I’ve heard many describe as a bit of a Mary sue for Heinlein, himself.  In this one, Long is the oldest member of the families but not an active one.  He left Earth before the Prophet and spent time bouncing around the solar system being, I guess, irascible and getting in and out of troubles.  He’s used, in this story, as a character who is NOT convinced of the rightness of the covenant and responsibility of the government.  He is, instead, far more ready to break laws and force his will on others.  He even complains that the people in the current time are much tamer and tighter-wound than when he was a boy in the early 20th century.  Hell, just quickly I think a court could pin on him, in addition to grand theft starship, piracy, filing a false flight plan, breaking and entering, interference with a policeman, assault and battery, assault against a law enforcement office, kidnapping and likely a few others.  He is more David McKinnon with eyes open that he’s like the rest of the families.
Another, very interesting to me, character is Ellen Johnson.  She’s a background character used to show some of the effect of events on the standard family members.  She first appears with a small baby when the families are rounded up.  She is determined that, when they try their escape, that even if she gets left behind, the child gets to go.  Later, on other worlds, she pops up, continually thinking about her son and raising him and doing what she thinks is best for him.  In the end, he sneaks away to board the ship when she decides to stay behind on a planet and not return to Earth.
It occurred to me, reading this, that Ellen is a Heinlein matron as she develops.  Instead of being the annoying matron that we see most of the time, instead this shows her growing and becoming her role.  It’s a lot more sympathetic.  She’s not a particularly strong personality, but she does try to learn to control her life and the circumstances of her child.  Over time that grows more controlling (according to the boy) until he tries to break free and she follows him instead.  I think that’s a great ‘Heinlein matron’ in a capsule and does make them more understandable.  Interesting reading, there.
Methuselah’s Children also moves the opening dates for the Future History chart back to the creation of the Howard Families in the 1870s.  That’s as far back as the revision goes, to the best of my knowledge.
Oh, interesting note at the end:  this version of the story ends with “TO BE CONTINUED in Time Enough for Love”  The source for this version is the 1967 printing of The Past Through Tomorrow.  Was that in there?  I don’t recall it but it’s been ages since I’ve seen my copy of that one (and mine would have been the 80s paperback so it might have been removed).  It would make sense that the 1967 release, for the last story in the book, would push and upcoming book.  But TEFL would be published six years later, in 1973.  Seems like a long time.