Steve Martin’s The Pleasure of My Company?
If so, I may set a new record for easiest one:
“In my younger and more vulnerable years my father gave me some advice that I’ve been turning over in my mind ever since.”
Yup. Personal fave, thank you.
By sheerest coincidence, I had just checked in his new biography Born Standing Up, so my mind was on him. Don’t know if I could have pulled it out otherwise.
Don Juan by Lord Byron.
The Great Gatsby by F. Scott Fitzgerald.
“This time there would be no witnesses.”
“There were crimson roses on the bench; they looked like splashes of blood.”
Strong Poison by Dorothy Sayers
“Snow was falling on Riverside, great feather-white puffs that veiled the cracks in the facades of its ruined houses, slowly softening the harsh contours of jagged roof and fallen beam.”
Gotten:
“I want a hero…”: Don Juan, by Lord Byron.
“One Christmas was…”: A Child’s Christmas in Wales, by Dylan Thomas.
“I am always drawn…”: Breakfast at Tiffany’s, by Truman Capote.
“Death was driving…”: Winter Moon, by Dean Koontz.
“News item from…”: Carrie, by Stephen King.
“She was born a thing…”: The Ship Who Sang, by Anne McCaffrey.
“The thousand injuries…”: “The Cask of Amontillado,” by Edgar Allan Poe.
“The essential Saltes of Animals…”: “The Case of Charles Dexter Ward,” by H. P. Lovecraft.
" ‘There are dragons…’ ": A Wind in the Door, by Madeleine L’Engle.
“This all started…”: The Pleasure of My Company, by Steve Martin.
“In my younger and more vulnerable years…”: The Great Gatsby, by F. Scott Fitzgerald.
“There were crimson roses…”: Strong Poison, by Dorothy Sayers.
And here are the ones that have not yet been guessed:
“AUTHOR: Frederick the Great, King of Prussia, came to power in 1740.” (can’t believe nobody’s gotten this one yet! what kind of geeks are you?!)
“It begins, as most things begin, with a song.”
“Death came for him by mistake.”
“Snow was falling on Riverside, great feather-white puffs that veiled the cracks in the facades of its ruined houses, slowly softening the harsh contours of jagged roof and fallen beam.”
“This time there would be no witnesses.”
“THERE were four of us - George, and William Samuel Harris, and myself, and Montmorency. We were sitting in my room, smoking, and talking about how bad we were - bad from a medical point of view I mean, of course.”
“The first facet was purpose.”
“The primroses were over.”
“I went down to the Piraeus yesterday with Glaucon, son of Ariston, to pray to the goddess; and, at the same time, I wanted to observe how they would put on the festival, since they were now holding it for the first time.”
“It began as a mistake.”
“In a distant and second-hand set of dimensions, in an astral plane that was never meant to fly, the curling star-mists waver and part . . .”
“This time there would be no witnesses.”
Dirk Gently’s Detective Agency
“THERE were four of us - George, and William Samuel Harris, and myself, and Montmorency. We were sitting in my room, smoking, and talking about how bad we were - bad from a medical point of view I mean, of course.”
Three Men in a Boat
“The primroses were over.”
Watership Down
Three Men in a Boat (To Say Nothing of the Dog)
I didn’t find any of these, but here’s another one :
“For a long time I used to go to bed early”
Gaiman, Anansi Boys.
New: “There’s a light on in the attic.”
Hint: It’s shelved in non-fiction.
Plato’s Republic.
“All states, all powers, that have held and hold rule over men have been and are either republics or principalities.”
“The Empire, having long been divided, must unite; having long been united, must divide.”
The Prince, Nicolo Machiavelli.
“We were on our way to the colmado for an errand, a beer for my tìo, when Rafa stood still and tilted his head, as if listening to a message I couldn’t hear, something beamed in from afar.”
Yup!
Affirmative.
Got it in one. 
Two more:
“Miss Brooke had that kind of beauty which seems to be thrown into relief by poor dress.”
“When he was thirteen, my brother Jem got his arm badly broken at the elbow.”
(Since that one was probably way too easy: )
“Midway in the journey of our life I came to myself in a dark wood, for the straight way was lost.”
To Kill a Mockingbird.
“In the ancient city of London, on a certain autumn day in the second quarter of the sixteenth century, a boy was born to a poor family of the name of Canty, who did not want him.”
The Prince & The Pauper, Mark Twain.
“One evening of late summer, before the nineteenth century had reached one-third of its span, a young man and woman, the latter carrying a child, were approaching the large village of Weydon-Priors, in Upper Wessex, on foot.”
Anybody want to try Post #52?
Dante’s Inferno.
“It was a dark and stormy night.”
Is that Hardy’s The Mayor of Casterbridge?
And that a ‘No’ on 52.
Hardy is correct.
What if I give you a hint on #52?
Snoopy.
[It wasn’t B-L]
What’s the hint for #52?
Actually, IIRC, Snoopy was quoting some old-time author whose name I can’t recall ( and I refuse to google-cheat ), who was well regarded in his day, but these days is mostly known for that one line.