If you haven't read my review of Ayn Rand's "The Fountainhead" from 2019, you should definitely do so for a meager explanation and scientist's opinion of individualism (after you've read the book of course!).
A common critique of The Fountainhead and Atlas Shrugged is how long they are.
The philosophy of individualism is incessantly drummed into your head for both 700+ page books (I have not read Atlas Shrugged but from my understanding it's much like The Fountainhead but more drawn out).
Alright, now imagine the same amount of philisophical content from either book smashed into ~100 pages.
That is my best description of "Anthem".
Rand does not waste a page reminding you of how awesome it is to be your own goddamn person and rely on yourself.
(A massive revelation in the book is the rediscovery of the word "I".)
Anthem takes place in a dystopian future where the ultimate sin is to think you're different or better than anyone else.
Names are forbidden (everyone has an identifying number, such as the protagonist, Equality 7-2521), families are forbidden, creativity is forbidden.
One day the main character finds a bunker in the woods that contains technology of the past, including electricity.
Over the course of the book he does several experiments in the bunker, reclaims knowledge of the past, and in the meantime kindles a forbidden relationship with a woman (the beautiful Liberty 5-3000).
Eventually he presents his works to the society elders and is rejected. He leaves with his girlfriend and builds a new self-reliant utopia... where he is in charge of other people. Hm...
I can't say Rand's philosophy makes the most practical sense (to me, at least), but it was an entertaining read.
If you're a sensible human who can't be bothered with an absolute unit of a book (i.e. The Fountainhead, which I will nonetheless recommend due to its complex characters and relationships) but want to know what individualism is all about, give Anthem a read (or listen at https://www.youtube.com/watch?v=NPeQ2U3Vmc4).