The Graphics programming section is so brief and I can’t seem to find any books or tutorials on UE4 Rendering, which will help in understanding UE4 rendering. 
What part of the UE4 rendering engine are you wanting to replace? Implementing your own rendering solution is extremely difficult. There is no book out there that will give you all the knowledge required to replace the UE4 rendering solution.
The main reason is the amount of knowledge required is extreme. Most of the knowledge required for cannot be taught, it requires experience to be able to do the kinds of things you have been asking lately.
What is the reason why you are wanting to replace and/or modify the rendering engine? What is your end goal here, is there a missing that you want to have implemented? Are you looking to create your own game engine?
Answers to those questions are what we need be able to help you further. As you have already found out, it is an extremely complex topic, but what you are looking to create may be much simpler within the current rendering engine. Please let us know so we can try ans help you!!! 
I want to achieve rendering quality as that of films in real time.So I want to modify the rendering engine.I have got which books to study for theory and mathematics but I’m struggling to find Books on graphics programming.
I’m confused between these books:
My only concern is that UE4 graphics programming documentation is so brief.They should add more content to it.It can be tutorials or books.
Are there actually any decent UE4 books in general available? I bought the Art of Unreal Engine 4 (Book 1 & Extra Credits), and tbh it doesn’t really help at all lol.
I’ve been re-working the first two books into more of a comprehensive guide with more of a focus on the “Why things work” - Hopefully, it’ll be more helpful then the others! It should be released for free on these forums in the next few weeks.
Excellent,
I would love to get a complete reference guide to UE4 BPs/C++ classes, although I doubt there will ever be a paper version of that lol
Things change ALL the time but it IS possible. That’s what the documentation is for though, isn’t it? 
Yeah true, I just like reading from a real book, instead of onscreen. I’m already running 3 monitors and having docs open means getting another monitor (which I intend to do, lol)
I guess I could whip up a dictionary-type thing with Blueprints / C++ classes, which state they are and what do (And are used for). Less in the style of the documentation but more in the style of a classic dictionary. It won’t be done overnight though. If you want it, I’ll do it though. I can see it helping quite a few people out.
That would be excellent. A reference to BP nodes/functions/etc. I currently find that I need something but don’t know the name of the node, so a reference would be great. If you make a physical book of it i will buy that too 
Sure thing. I don’t have an ETA for it as it will take quite a while to put together but it’ll be done when it can be! 
Guys can someone guide me among these books - My only concern with 3D Game Programming is it uses D3DX library which has been deprecated.So Should I go for the other book or should I go for 3D Game Programming book and ignore D3DX(which I think would be hard) ?