I see 3 outcomes, in order of least to most in likelihood and excitement:
Julius see's the error in his ways and establishes what essentially is an entirely new politcal system that is so good and just that It would stand today.
Same scenario as above except his grandson grows up to one day claim his rule and reverses everything.
He is killed, and for the exact same reasons as current lore. Either because his arrogance causes him to deny what will happen, or because regardless of any attempt to avoid such an outcome those who sought the power he had would still seek out that same power. Both lessons are fairly important but I think the latter one is often missed in the countless retellings. Power both corrupts and it's one sexy hot bitch.
From what I can tell, the "tyranny" that Caesar was killed for was because he wasn't for the Roman ownership class and was using his power to counteract the huge wealth disparities that existed at the end of the Roman Republic.
Side question, but would ancient Romans be able to decipher a modern day language from one book? I'd imagine a language with Latin based words might be easy enough but not sure how equipped they were.
He couldn't get himself to read a note an eavesdropper to the conspirators gave him trying to warn him about the attack, I sadly doubt he'd read a whole prophetic book.
Have it printed on a series of cave walls that go deep into the ocean and by the time the present comes around again, maybe we'll have fully explored the oceans and there will still be unexplored land.
I'd love to send Einstein's Theory of General Relativity to Newton. Or maybe a whole textbook on modern physics but that would probably not be deep enough for him. But I'd really love to see what he could have done with modern physics.
Some people are just one hit wonders, so it could be für nothing. But it would be worth a try.
It's definitively better than to give the idea of nuclear fission to Henry Cavendish in 1766. Right now we live in the sweet spot between discovery and... broad practical application.
The complete history of the stock market. I'd send it to me for my 21st birthday. With a certain letter proving it was me from the future. With the last chapter being the history of bitcoin.
I wonder how long it would take to start diverging. There's a maximum volume of trades you can make before you start having an impact on the prices yourself. Knowing the future perfectly means eventually you would be the most dominant force on the market unless you tempered yourself. But having a book is just having a snapshot of a single reality that your reality will start diverging from.
The show The Travelers addresses this a bit, but I think even that one underestimates how much a new player will full knowledge of the future market would affect that future market.
One of my college text books on Electromagnetism with the heavy calculus and derivations of Maxwell's Equations to either Leonhard Euler or Isaac Newton, one of the extremely few people in the 17th century that would be able to understand the math and use the math to actually generate electricity.
Please reconsider avoiding Newton if you are offered the opportunity to send a book back in time. He was a narcissistic dick who used his influence to fuck over other academics (Leibniz, Hooke), and plagiarized and stole the work of others without crediting them (Flamsteed).
Hitler was egomaniacal I don't think he would have a change of heart, but instead use any information too alter the outcome.
But if you're going to send a book to one of the worst people in history it's gotta be one of the worst books in history. Just gotta find the right age to send him The Game: Penetrating the Secret Society of Pickup Artists by Neil Strauss. I need AI to get to the next level so I can see how this might play out.
We're in the timeline where he was stopped and had to kill himself, not sure I really want to give him any pointers about how to further his agenda but slightly differently and avoiding some tactical mistakes. I don't think he's going to take from the book that his world view was wrong or that for the good of Germany he should abandon his goals.
That book would inform him that if he starts a war to expand Germany, the actual result will be to make Germany a lot smaller, divided into a liberal and a communist state (until the communist one gets absorbed into the liberal one), and him remembered as possibly the worst person to have ever lived.
I like to imagine giving a big World Atlas of some sort to any seafaring culture around 500AD would result in interesting consequences, possibly with it becoming a real treasure. Maps are like pictures and valuable even if the places' names can't be understood
Quite like to send the Complete Works of William Shakespeare back to the guy himself. Seeing he's already written it that would free him up to write a whole bunch more.
Would be cool to do the same thing with certain scientists.
I'd like to prevent many tragedies, but I'm not sure a single book would change history. I can actually imagine it going very wrong...
— Mein Führer, this book here explains our theories about the origin of the German population and about the natural maliciousness of Jews are wrong.
— Let me see... Lies, all lies! This here is evidence of their pervasive propaganda against the aryan people.
— Witchfinder General, a book had arrived... from the unknown.
— What kind of sorcery is this? "Witches do not exist". "...These trials were the result of ignorance and greed". What in the name of God is this blasphemy? A powerful witch is near and these are her evil tricks!
A book on how to make weapons or improve trade, so that people will try it out.
But after the first 3 items or so(to show that the book is legit) we shift to stuff that accelerates science very much.
Get them to create electricity and radio waves earlier.
Society gets to progress faster.
Tho, who should it be sent to? Someone religious? In that case it'd be better to mask it as a religious text, where god is revealing the workings of the universe and encouraging humans to find out more about his design by observation and experimentation?
A science book and a noteworthy thinker. But probably not terribly far back. It's not like knowledge of electricity would go terribly far before other technologies (manufacturing, for sure) were ready to enable it to flourish.
Probably not. It was likely Paul that introduced the apocalyptic stuff. There were other sects with very different attitudes about time in general, which were declared heretical by Paul himself in his letters to Corinth where he lambasted them for following a different version of Jesus and was saying they shouldn't get married and should give their lives to his church because the end times were near (and also to give him lots of money).
Without any context, I was going to respond with "does a bear shit in the woods" since annoying mods has been a concern since time immemorial, but then I saw what you meant.