Threshold

The doorway is passable, but few are ready yet to cross the threshold and enter the hallway beyond.

The Hitchhiker series by Douglas Adams follows the adventures of the last surviving man, Arthur Dent, after the demolition of the Earth by a Vogon constructor fleet to make way for a hyperspace bypass.
Arthur Dent is rescued from destruction on Earth by escaping, ironically, on a passing Vogon spacecraft with Ford Prefect, a human-like alien writer for the namesake electronic travel guide.
He explores the galaxy with Prefect and eventually encounters another human, Trillian, a beautiful woman who had also escaped Earth in the nick of time.
Other characters include the two-headed President of the Galaxy, Zaphod Beeblebrox, and a depressed and paranoid android robot, Marvin.
Update April 22, 2023: Back to Bizarro Land, again. I had been told to exercise (not walk in dark until I dropped); more precisely: do yoga. continue

In a dark sea of centuries wherein nothing seemed to flow, a lifetime was only a brief eddy, even for the man who lived it. There was a tedium of repeated days and repeated seasons; then there were aches and pains, and finally Extreme Unction.
And a moment of blackness at the end – or at the beginning, rather.
For then the small shivering soul who had endured the tedium, endured it badly or well, would find itself in a place of light, find itself absorbed in the burning gaze of infinitely compassionate eyes as it stood before the Just One. It would be hard to believe differently.
A Canticle for Leibowitz (1959) by Walter Miller