In no specific order, omitting political stuff and obviously having some bias towards my present recollections, I'd say:

Confessions of a Philosopher by Bryan Magee
The World as Will and Representation by Arthur Schopenhauer
Real Materialism and Other Essays by Galen Strawson
What Kind of Creatures Are We? by Noam Chomsky
The Knowing Animal by Raymond Tallis
Cosmosapiens by John Hands
Novel Explosives by Jim Gauer
V. by Thomas Pynchon
Hard Boiled Wonderland and The End of The World by Haruki Murikami
A Brief History of Seven Killings by Marlon James

-"Outlines of Pyrrhonism" by Sextus Empiricus
-"Phenomenology of Perception" by Maurice Merleau-Ponty
-"Discipline and Punish" by Michel Foucault
-"Structure of Scientific Revolutions" by Thomas Kuhn
-"Conjectures and Refutations" by Karl Popper
-"Gestalt Psychology" by Wolfgang Kohler
-"De Oratore" by Cicero
-"I Ching" (Wilhelm translation)
-"Zhuangzi"
-"Liezi"

Some other honorable mentions include: "Institutio Oratoria" by Quintilian, "Critique of Pure Reason" by Immanuel Kant, "Art of War" by Sunzi, "Hereditary Book on the Art of War" by Yagyu Munenori, "Book of Five Rings" by Miyamoto Musashi, "The Unfettered Mind" by Takuan Soho, "Daodejing", "Huahujing", "Psychology from an Empirical Standpoint" by Franz Brentano, "Psychological Types" by CG Jung, "Laboratory Life" by Latour and Woolgar, "Die Weisheit der Hunde" by Georg Luck (collection of most if not all fragments from the cynics), "The Ego and His Own" by Max Stirner, "One-Dimensional Man" by Herbert Marcuse ...

I'm liking the Schopenhauer :up: .. And Benatar ain't bad either, darth.

One Flew Over the Cuckoo's Nest

Jiddu Krishnamurti

but mostly....

San Felasco State Park - that is, the real world.

Introduction to Topology and Modern Analysis by George F. Simmons (1963)

The World as Will and Presentation – Arthur Schopenhauer
Outlines of Pyrrhonism – Sextus Empiricus
Ficciones – Jorge Luis Borges
The Incredible Shrinking Son of Man – Robert Price

Two novels, offhand:

• The Fountainhead - Ayn Rand
• Hold Back This Day - Ward Kendall

Hold Back This Day - Ward Kendall — Gladiator of Truth

I hadn't heard of Hold Back This Day, so I looked it up. Most of the reviews I found are in white nationalist publications/websites. You won't find much sympathy for those views here on the forum. Most people who follow that path quit or are banned pretty quickly.

Probably the most 'landmark' books for me:

William Connolly - Identity\Difference
Slavoj Zizek - The Sublime Object of Ideology
Maurice Merleau-Ponty - Phenomenology of Perception
Gilles Deleuze - Difference and Repetition
Ludwig Wittgenstein - Philosophical Investigations
Hannah Arendt - The Human Condition
Ellen Meiksins Wood - The Origin of Capitalism

My mind draws a complete blank. Either I've forgotten all that I've read (Alzheimer's :sad: ) or never read any (Moron :sad:) or I read but couldn't understand a damn word (Voynich manuscripit, Rohonc codex :sad: ) or the book was blank from cover to cover (A Record Of The Statesmanship And Political Achievements Of Gen. Winfield Scott Hancock, Regular Democratic Nominee For President Of The United States (1880) :sad: ).

Didn't realize there were so many ways to fuck up! There's more than one way to skin a cat - many was of becoming the (village) Idiot (Dostoevsky. I recall borrowing that book, maybe I have it on a shelf somewhere, never got around to flipping through it though).

Which books have had the most profound impact on you?

"Iyyôbh" & "Qōheleth" (Tanahk)
Ping fa, Sunzi
De rerum natura, Lucretius
Outlines of Pyrrhonism by Sextus Empiricus
Ethics, Benedictus de Spinoza
Friedrich Nietzsche (Walter Kaufmann transl.)
• Beyond Good and Evil
• On the Genealogy of Morals
• Twilight of the Idols
The Conquest of Bread, Pyotr Kropotkin
The Souls of Black Folk, W.E.B. DuBois
"The Last Messiah" (essay), Peter Wessel Zapffe
Ludwig Wittgenstein
• Tractatus Logico-Philosophicus
• On Certainty
I and Thou, Martin Buber
The Rebel, Albert Camus
Phenomenology of Perception, Maurice Merleau-Ponty
Life of the Mind, Hannah Arendt
Totality and Infinity, Emmanuel Levinas
Oeuvre of George Steiner
Gnostic Religion, Hans Jonas
Oeuvre of E.M. Cioran
From Being to Becoming, Ilya Prigogine
Freedom in the Making of Western Culture, O. Patterson
Albert Murray
• The Omni-Americans
• The Hero and the Blues
• Stomping the Blues
James Baldwin
• Notes of a Native Son
• Nobody Knows My Name
• The Fire Next Time
• No Name in the Street
Why We Can't Wait, Martin Luther King, Jr.
God in Search of Man, Abraham Heschel
The Gnostic Gospels, Elaine Pagels
Dreamtime, Hans Peter Duerr
Dao De Jing, Roger Ames, David Hall & Laozi
Critique of Cynical Reason, Peter Sloterdijk
Natural Goodness, Philippa Foot
The Sovereignty of Good, Iris Murdoch
The Fragility of Goodness, Martha Nussbaum
Oeuvre of Carl Sagan
Philosophy as a Way of Life, Pierre Hadot
Joyful Cruelty, Clément Rosset
Being No One, Thomas Metzinger
"Three Pound Brain" (blog), R. Scott Bakker
God: The Failed Hypothesis, Victor J. Stenger
After Finitude, Quentin Meillassoux

(short list)

Cant say - have at this stage in life an entire library inside and I am not the librarian --- sadly. So to know exactly within my notions and to know which one of the thousands and thousands I have read within science, philosophy, psychology, novels and straight garbage - I do simply not know.

Because "profound impact" requires that you also know how this particular book changed you, altered your behavior and you person and in what way.
I would say that I was very very impressed by the books of Kant - all of them. The one that I read first: the first Critique was difficult due to the language he uses and thus understanding the concepts - but then when I had a grasp of it - I did not find the other all that difficult. What impressed me is the diligence that man had in explaining, thus the vast knowledge he possessed and the insights and the ability to explain this thoughts in a stringent and coherent manner.

I know - that reading his books sort of put my own neurons in "order" --- and that reading him helped me understand a lot that I did not know before I read his books - but I also held a critical approach to what he wrote and thus I read books of Jung and others in order to verify or find flaws - like Freges books that do refute some thoughts in Prolegomena (thus the first Critique ...) but...
Still...
Deep impact?
How am I to do "soul search" within that? I know that all I have lived, all I have read, and all that I have picked up and "put into my own rucksack" has formed me - but what particular part gave me more than others?
Maybe the books of HC Andersen, the brothers Grimm and the narratives (children's version) of Thousand and one night - when I was preschool - impact me in my core?
Who knows... no idea...

I started readin before school and never stopped and have been a reader of - all that I found interesting and were I could learn something about humans and life.

Mental Capacity Act 2005 - UK legislation
Waterland - Graham Swift
Contributions form a Potential Corpse - Eugene Halliday
Article 12 of the UNCRPD (and General Comment 1)
The Once and Future King - T. H. White
Defence of the Devil - Eugene Halliday
The Silmarillion - Tolkien
Loud Hands - collection of autistic writing
The Jungle Books - Kipling
The Marriage of Heaven and Hell - Blake
The Grey King - Susan Cooper
The Farseer Trilogy - Robin Hobb (and all the books set in that world)

Most of these affected me profoundly both emotionally and intellectually.

The Magpie Annual 1974.
The Littlewoods catalogue lingerie section.
TV guide.
The Bible.
Pear's Cyclopedia.
Dune - Frank Herbert.
Energy for Survival - Wilson Clark.
Darwin's Dangerous Idea - Daniel Dennett.
A Brief History of Time - Stephen Hawking.

"The Last Messiah", Peter Wessel Zapffe — 180 Proof

Not quite a book, but certainly a profound read.

Dune - Frank Herbert. — counterpunch

Agreed, what a great book.

That's three people who have said Outlines of Pyrrhonism. I have it on my shelf, but I have not read it yet. I'll have to read it soon.

I figured you'd appreciate the schop, he's pretty dope

Dune - Frank Herbert.
— counterpunch

Agreed, what a great book. — darthbarracuda

TV guide is pretty good too - but I find you have to stay current!

I included that essay and the two "books" from the Hebrew Bible thinking more broadly of "philosophical readings" than mere books. I couldn't be bothered with also adding fiction, poetry, works of science, histories and fuck all to my list which is long enough as is.

Tractatus-Logico-Philosophicus
Enchiridion
Meditations
Feeling Good: The New Mood Therapy

The Lord of the Rings-JRR Tolkien
The Silmarillion-JRR Tolkien
Dune-Frank Herbert
The Ethics-Spinoza
The World and Will as Representation-Schopenhauer
Beyond Good and Evil-Nietzsche
Enchiridion-Epictetus
The Tao Te Ching-Lao Tzu
Nietzsche and Philosophy-Gilles Deleuze

According to my parents, it was the only book that would get me to sleep. The profound impact was that I was not put up for adoption, I suppose.

-"Conjectures and Refutations" by Karl Popper — Ying

That one is delicious.

The Screwtape Letters - C.S. Lewis

(Screwtape is a devil instructing his nephew Wormwood on how best to turn humans away from God)

It is, no doubt, impossible to prevent his praying for his mother, but we have means of rendering the prayers innocuous. Make sure that they are always very “spiritual”, that he is always concerned with the state of her soul and never with her rheumatism. Two advantages will follow. In the first place, his attention will be kept on what he regards as her sins, by which, with a little guidance from you, he can be induced to mean any of her actions which are inconvenient or irritating to himself. Thus you can keep rubbing the wounds of the day a little sorer even while he is on his knees; the operation is not at all difficult and you will find it very entertaining. In the second place, since his ideas about her soul will be very crude and often erroneous, he will, in some degree, be praying for an imaginary person, and it will be your task to make that imaginary person daily less and less like the real mother—the sharp-tongued old lady at the breakfast table. In time, you may get the cleavage so wide that no thought or feeling from his prayers for the imagined mother will ever flow over into his treatment of the real one. I have had patients of my own so well in hand that they could be turned at a moment’s notice from impassioned prayer for a wife’s or son’s “soul” to beating or insulting the real wife or son without a qualm.

All of the Ringing Cedars of Russia books
Tao Te Ching
One straw revolution
Tales from the night rainbow
Dantes divine comedy
The kin of Ata
the hobbit

Which books have had the most profound impact on you?

In no particular order:

The Sickness Unto Death - Søren Kierkegaard
Meditations - Marcus Aurelius
The Will to Power - Friedrich Nietzsche
Paradise Lost - John Milton
The Conquest of Gaul - Julius Caesar
Perdido Street Station - China Miéville
A Brightness Long Ago - Guy Gavriel Kay

The Meaning Of The Creative Act - Nikolai Berdyaev
The I Ching
The Witch - David Lindsay
The Master and Margarita - Mikail Bulgakov

The way of Man - Martin Buber (ended up being a self-help book for me trying to be a better person)
Lord of the Rings - JRR Tolkien (my first English book, so it taught me to read English and sparked my love for fantasy and sci-fi)
The Law - I try not to break it, I work with laws when monitoring compliance, for product development and writing contracts
The Republic - Plato (my first philosophical text, created a friendship with my professor and got me interested in philosophy)

In no particular order and off the top of my head:

The Magus - John Fowles
The First and Last Freedom - Krishnamurti
Zen and the Art of Motorcyle Maintainance - Robert Pirsig
1984 - George Orwell
Zen Mind, Beginner's Mind - Shunryu Suzuki
The Central Philosophy of Buddhism - T.R.V. Murti.

How can a singular superlative be a list?