Doorways in the Sand by Roger Zelazny
A rather zany book.
Starting with the habit of telling chapters out of order -- a scene and then the backfill that got the narrator there. Also involving the narrator, a perpetual student (in precise accord with his cryogenically frozen uncle, who left him an allowance until he gets a degree) and an acrophile. And the setting, where first contact has been made, and we have been allowed to display an alien machine that inverts things and a star stone while the Mona Lisa and the British Crown jewels go on interstellar tour. And the French professor who was the narrator's advisor once and his past; a talking wombat and kangaroo; being asked whether he's prejudiced against plants; his old roommate's marriage; chemical isomers; and more.
I read this over a decade ago. When I heard it described recently, I thought I recognized it; parts definitely stuck in memory.