diff --git a/books.md b/books.md
index 3d822ae..72c9791 100644
--- a/books.md
+++ b/books.md
@@ -5,6 +5,7 @@ The following is a list of free, open source books on machine learning, statisti
 * [Real World Machine Learning](https://www.manning.com/books/real-world-machine-learning) [Free Chapters]
 * [An Introduction To Statistical Learning](http://www-bcf.usc.edu/~gareth/ISL/) - Book + R Code
 * [Elements of Statistical Learning](http://web.stanford.edu/~hastie/ElemStatLearn/) - Book
+* [Computer Age Statistical Inference (CASI)](https://web.stanford.edu/~hastie/CASI_files/PDF/casi.pdf) ([Permalink as of October 2017](https://perma.cc/J8JG-ZVFW)) - Book
 * [Probabilistic Programming & Bayesian Methods for Hackers](http://camdavidsonpilon.github.io/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers/) - Book + IPython Notebooks
 * [Think Bayes](http://greenteapress.com/wp/think-bayes/) - Book + Python Code
 * [Information Theory, Inference, and Learning Algorithms](http://www.inference.phy.cam.ac.uk/mackay/itila/book.html)
@@ -69,7 +70,7 @@ The following is a list of free, open source books on machine learning, statisti
 * [Probability & Statistics Cookbook](http://statistics.zone/)
 * [Advanced Data Analysis From An Elementary Point of View](http://www.stat.cmu.edu/~cshalizi/ADAfaEPoV/ADAfaEPoV.pdf)
 * [Introduction to Probability](http://athenasc.com/probbook.html) -  Book and course by MIT
-* [The Elements of Statistical Learning: Data Mining, Inference, and Prediction.](http://statweb.stanford.edu/~tibs/ElemStatLearn/) -Book
+* [The Elements of Statistical Learning: Data Mining, Inference, and Prediction.](http://statweb.stanford.edu/~tibs/ElemStatLearn/) - Book
 * [An Introduction to Statistical Learning with Applications in R](http://www-bcf.usc.edu/~gareth/ISL/) - Book
 * [Learning Statistics Using R](http://health.adelaide.edu.au/psychology/ccs/teaching/lsr/)
 * [Introduction to Probability and Statistics Using R](https://cran.r-project.org/web/packages/IPSUR/vignettes/IPSUR.pdf) - Book