TITLE: An easier reference than "On the Functional Equations Satisfied by Eisenstein Series"?
QUESTION [5 upvotes]: I'd like to learn about Eisenstein series so I started reading "On the Functional Equations Satisfied by Eisenstein Series"by Langlands. 
http://www.sunsite.ubc.ca/DigitalMathArchive/Langlands/pdf/Eisenstein-ps.pdf
I'd like to go through the first few chapters. 
I'm struggling already at Chapter 2 (where he goes through the background material basically) because I don't have enough Lie groups/Lie algebra background; at least this is what I think is the reason, I have only seen Lie algebra material over $\mathbb{C}$ and in the book it seems to work with some other field (I think $\mathbb{R}$) and stuff looks some what different...  
I was wondering if someone who knows this book could possibly recommend me an alternative (perhaps easier) reference to study similar material or possibly a reference to cover prerequisite to go through this book. Any comments/suggestions would be appreciated. Thank you very much.

REPLY [5 votes]: Professor Paul Garrett's book 
http://www-users.math.umn.edu/~garrett/m/v/current_version.pdf
treats many cases treated in Langlands' book although the comparison between them will not be easy. Also, Godement's Bourbaki article deals with it. 
http://www.numdam.org/article/SB_1966-1968__10__115_0.pdf
I have heard Moeglin-Waldspurger's book is easier than Langlands' and does the same thing but I have felt it more like 'this star is nearer than that star'...  I cannot reach either of them.