O'Reilly are offering a number of free programming books which a few of you may find useful.

I believe there are other books available in the /free/ section of their website.

Book titles:

Modern Java EE Design Patterns - Building Scalable Architecture for Sustainable Enterprise Development
Object-Oriented vs. Functional Programming - Bridging the Divide Between Opposing Paradigms
Java: The Legend - Past, Present, and Future
Introducing Java 8 - A Quick-Start Guide to Lambdas and Streams
A Whirlwind Tour of Python
20 Python Libraries You Are not Using (But Should)
Hadoop with Python
How to Make Mistakes in Python
Functional Programming in Python
Python in Education
Picking a Python Version: A Manifesto
Trends Shaping the London Tech Scene
2016 European Software Development Salary Survey
2016 Software Development Salary Survey
Why Rust?
C ++ Today
Visualizing and Analyzing Data with F #
RxJava for Android App Development
Swift Pocket Reference