I don't play the Reti so cannot offer advice. But, try to look for thematic tournaments where the position is set-up for the opening. It makes for great practice and learning the opening from both sides. Good luck.
Books on the Reti
Starting Out: The Reti by GM Neil McDonald (2010)
http://www.jeremysilman.com/shop/pc/Starting-Out-The-Reti-76p3799.htm

That isn’t quite what I’ve asked for and I haven’t found anything on my question. Thanks for the response nonetheless.

I’m not particularly keen on transposing into main lines and I'd like to stay in Reti lines against c5, KID, and the Grunfeld. I was wondering if there’s any book on said lines or if I’d have to come up with these responses by myself with a database and experimentation. Thanks!

>8 - You can't always stay in Reti territory. For example, in lines with an early c5, there is no Reti. You end up in a Symmetrical English instead (i.e. 1.Nf3 c5 2.c4 is an English, not a Reti).

I would suggest How Ulf Beats Black. It does not remain in Reti territory 100% of the time, and does transpose to KID and Catalan in particular, but the line against the KID is more in line with what a Reti player is looking for and not the wild lines that Black gets in the main lines of the King's Indian.
Here's what I recall it covering:
Exchange KID
Anti-Grunfeld (meaning you are in English/Reti territory there)
Catalan
Exchange Slav
Reti Accepted (2...dxc4)
Reti Advanced (2...d4)
Double Fianchetto (i.e. g3/Bg2, b3/Bb2 all played in the first 7 or 8 moves against certain responses by Black.
I have the Cadogan easy guide to the Reti Opening by Angus Dunnington. It's pretty basic and doesn't appear to cover the things you asked about.
marknatm wrote: "I have the Cadogan easy guide to the Reti Opening by Angus Dunnington. It's pretty basic and doesn't appear to cover the things you asked about."
https://www.chesscafe.com/text/easyreti.txt
Possibly of interest:
Dynamic Reti by GM Davies
https://web.archive.org/web/20140627005248/http://www.chesscafe.com/text/hansen64.pdf
The Modernized Reti
https://www.newinchess.com/media/wysiwyg/product_pdf/7780.pdf
Starting Out: The Reti by GM Neil McDonald (2010)
https://web.archive.org/web/20140627101228/http://www.chesscafe.com/text/hansen131.pdf


Is the modernized Reti good? Thanks to everyone that responded! I’m reading The Modern Reti: Anti-Slav Repertoire combined with English opening knowledge right now. The Ulf books sounds really great so thanks Thriller! C:

I mean, I might dedicate myself to the Ulf book, love the way it’s quiet and how you don’t play for a HUGE advantage out of the bat but understanding of the position will carry you to a victory.
I dont play much on my chess.com account but I've heard the forums here are good! I'm looking to try out the Reti and am looking for reading material. Are there any books or set of books that have a repertoire approach to this where they cover most of the responses? I’ve heard the Modern Reti: Anti-Slav Repertoire is good but it lacks responses to the KID, c5, and Grunfeld so I’m also looking for something to fill in those holes. Thnks (: