“I like this book, I really do! You will like it, if you read it too!!” Dr. Seuss
“This book should be required reading. That’s not an expression- I really mean it. Armed federal agents should break into your home and kill you if you don’t read it.” - Michael Moore
“This is the reason God created Cliff Notes.” - Cormac McCarthy
“Though J.D. Salinger is tragically gone, I am confident this book will carry on his tradition and inspire future generations of misfits, freaks, losers, and serial killers.” - Mark David Chapman
Oh, ouch. 
“I am compelled to say that this is doubleplus good. You will read it, and you will enjoy it.” George Orwell.
“I can’t read.” – F. Scott Fitzgerald
“This book is laugh-out-loud, side-slittingly, spit-out-your-coffee funny! That it’s about the death camps of Pol Pot is secondary.” -Stephen Ambrose
“Can’t put it down. Literally!” --Edward Scissorhands
“Great with fava beans and a nice chianti.” --Hannibal Lecter
“The best 10 inches in my life!” --Ron Jeremy
“A way to pass time!” --Sir Thomas Crapper
“Arf!” --Max the golden retriever
“From the moment I picked this book up until I laid it down I was convulsed with laughter. Someday I intend on reading it.” --Groucho Marx
(Actually a paraphrase of a real quote, I just like it a lot.)
“THIS is the reason I invented the printing press.” - Johann Gutenberg
“Classier than a frat house circle-jerk.” - Larry Flynt
“The most convincing fiction since the Holocaust.” - Mahmoud Ahmadinejad
“If you don’t have a TV, an XBox, a Wii, or a Gameboy, I suppose there must be SOME worse way to kill an hour than by reading this book.” - Greg Heffley
[Austrian accent] “This book is super fantastic!!!” [/Austrian accent]–Arnold Schwarzenegger
“After landing at the sparkling new high-tech airport in in Beijing, which far outshines any airport in the increasingly decrepit United States, I took a taxi to the mega-modern hotel where the world economic summit was being held. The taxi driver told me, “The Earth is becoming a much smaller place.” His words echoed in my brain, as I realized that Walt Disney was right: it’s a small world after all, albeit one in dire need of more investment in its educational infrastructure… where was I? Oh yeah, read this book.” -Thomas Friedman
“I wish to heaven I had never laid eyes on the maddening horrors so magnificently carved in the bas reliefs of that cyclopean underwater city, or those stupendous nightmares described in the mad screeds of Abdul Alhazred. I feared I would no longer take delight in the things of this world, and my dreams would ever be filled with phantastical images of the dread Old Ones. All that was left for me was to read this book, which was recommended by a dear old colleague and professor from Miskatonic University. I must confess, now, the truth; it wasn’t very good.” - Oswald Whateley
“This book was manufactured in a Deltrex 97-50 printing press, which left its mark on the microscopic irregularities of the back cover, which when I run my fingers across it reminds me of the perfect yet irregular surface of my wife’s inner left thigh.” – Nicholson Baker
“Not fucking bad. Not fucking bad at all.” David Mamet
“I loved the fuck scenes.” Plutarch.
“Mercifully short.” --Stephen King
“Definitely not one of my pseudonyms.” J.K. Rowling
“The single best book without fart jokes ever written!” --François Rabelais