Yes, I actually own this Signet paperback, Second Printing, September 1962. (Although the cover price is 50¢ instead of the pictured 35¢.) Clicking on the image will take you to the Amazon page where (as I type) you can grab this edition for $33.30! Advertised in "Acceptable" condition. (I assume this means it's pretty beat up, but has all its pages, and is still technically legible. Like mine.)
So anyway: it's another book down on the "Reread Heinlein" project; only 19 to go! The Wikipedia page tells us that its origins are from a three-part serialization in Astounding in 1941. (And there are links that will take you to that version!) It was pasted up into its novel form in 1958.
The main character is Lazarus Long, member of the long-lived Howard Families. Who are the product of selective breeding for longevity. Most of their members are masqueraded from society at large, inventing new identities as needed to hide their eternal youth. But some are out of the closet, and "society at large" has become convinced that they are hiding their actual secret. And the clamps are about to come down! Extermination of the Howards seems likely.
But Lazarus and his comrades come up with an audacious scheme: to swipe a convenient starship, load the Howards into it, and take off for a likely G2 star. Assisting is a fellow Howard, Andrew Jackson Libby. Who's had an interesting idea for a near-lightspeed space drive…
That's about the first 60% of the book; the remainder describes the Howards' wanderings to a couple planets, both inhabited by (seemingly) friendly, intelligent species. But each has its drawbacks.
Not too shabby for an 80-year-old yarn.