Update README.

Author: trekhleb

README.md

@@ -19,7 +19,7 @@ _Read this in other languages:_
 [_Español_](README.es-ES.md),
 [_Português_](README.pt-BR.md)
 
-*Note that this project is meant to be used for learning and researching purposes 
+*☝ Note that this project is meant to be used for learning and researching purposes 
 only and it is **not** meant to be used for production.*
 
 ## Data Structures
@@ -296,9 +296,3 @@ Below is the list of some of the most used Big O notations and their performance
 | **Shell sort**        | n&nbsp;log(n)   | depends on gap sequence   | n&nbsp;(log(n))<sup>2</sup>  | 1         | No         |           |
 | **Counting sort**     | n + r           | n + r               | n + r               | n + r     | Yes       | r - biggest number in array |
 | **Radix sort**        | n * k           | n * k               | n * k               | n + k     | Yes       | k - length of longest key |
-
-## The Book
-
-We’re writing a book that will clearly explain, in detail, the main algorithms. 
-If you’d like to be notified when the “JavaScript Algorithms” book 
-launches, [click here](https://upscri.be/402324/).