Free books are always nice. There are a fair number of textbooks released regularly under the Creative Commons or GNU Free Documentation Licenses, and not surprisingly many of them are on IT subjects…oh, and on discrete mathematics. (We hear ITM students may need a little boost there.) These books may be a good supplement to a course or may just help you learn something new on your own.

Term Papers
Choosing & Using Sources: A Guide to Academic Research https://osu.pb.unizin.org/choosingsources/

Networking
An Introduction to Computer Networks by Peter Lars Dordal http://intronetworks.cs.luc.edu/
Computer Networking : Principles, Protocols and Practice by Olivier Bonaventure http://www.saylor.org/site/wp-content/uploads/2012/02/Computer-Networking-Principles-Bonaventure-1-30-31-OTC1.pdf
Open Networking by Enric Peig Olivé (FTA) http://www.ftacademy.org/sites/ftacademy.org/files/materials/Open-Networks_v2.0.3.pdf

C++
Structured Programming with C++ by Kjell Bäckman http://bookboon.com/en/structured-programming-with-c-plus-plus-ebook
Programming Fundamentals – A Modular Structured Approach using C++ by Kenneth Leroy Busbee http://open.umn.edu/opentextbooks/BookDetail.aspx?bookId=144

Java
Introduction to Programming Using Java, Seventh Edition by David J. Eck http://math.hws.edu/javanotes/
Object Oriented Programming using Java by Simon Kendal http://bookboon.com/en/object-oriented-programming-using-java-ebook
Java: The Fundamentals of Objects and Classes – An Introduction to Java Programming by David Etheridge http://bookboon.com/en/an-introduction-of-java-programming-ebook
Think Java by Allen B. Downey https://archive.org/details/ost-computer-science-thinkapjava
Java, Java, Java: Object-Oriented Problem Solving by Ralph Morelli & Ralph Walde http://www.cs.trincoll.edu/~ram/jjj/
Think Java: How To Think Like a Computer Scientist by Allen Downey& Chris Mayfield http://greenteapress.com/thinkjava6/

Python
Getting Started with Python (IBM) https://bigdatauniversity.com/resources/getting-started-with-python/
Dive Into Python (free Python book for experienced programmers) http://www.diveintopython.net/
Think Python 2nd Edition by Allen B. Downey http://greenteapress.com/wp/think-python-2e/
An Introduction to Python by Guido van Rossum and Fred L. Drake, Jr.

Data Management
Database Design – 2nd Edition by Adrienne Watt & Nelson Eng https://opentextbc.ca/dbdesign01/
Database Fundamentals (IBM) https://bigdatauniversity.com/resources/database-fundamentals/
Database Design and Implementation – A practical introduction using Oracle SQL by Howard Gould http://bookboon.com/en/database-design-and-implementation-ebook
Big Data – Beyond the Hype: A Guide to Conversations for Today’s Data Game (IBM) https://bigdatauniversity.com/resources/big-data-beyond-the-hype/
An Introduction to R – Notes on R: A Programming Environment for Data Analysis and Graphics by W. N. Venables, D. M. Smith and the R Core Team https://cran.r-project.org/doc/manuals/R-intro.pdf

Linux and Open Source
Linux for IT Managers Course Guide by Nicholas Kimolo https://archive.org/details/ost-computer-science-linuxitmanual_pdf
GNU/Linux Basic operating system (FTA) http://www.ftacademy.org/sites/ftacademy.org/files/materials/fta-m2b-glbasic.pdf
Getting Started with Open Source development (IBM) https://bigdatauniversity.com/resources/getting-started-with-open-source-development/
Producing Open Source Software: How to Run a Successful Free Software Project by Karl Fogel http://producingoss.com/
Introduction to Free Software (FTA) http://ftacademy.org/sites/ftacademy.org/files/materials/fta-m1-intro_to_FS-v1.pdf
Implementation of free software systems (FTA) http://ftacademy.org/sites/ftacademy.org/files/materials/fta-m8-fs_imp.pdf
Legal Aspects of the Information Society (FTA) http://ftacademy.org/sites/ftacademy.org/files/materials/fta-m6-legal_aspects.pdf
Economic aspects and business models of Free Software (FTA) http://ftacademy.org/sites/ftacademy.org/files/materials/fta-m5-economic_models.pdf
Tools and Utilities in Free Software (FTA) http://ftacademy.org/sites/ftacademy.org/files/materials/fta-m10-fs_tools.pdf

Web
The Missing Link: An Introduction to Web Development and Programming by Michael Mendez http://textbooks.opensuny.org/the-missing-link-an-introduction-to-web-development-and-programming/
Introduction to Web Applications Development (FTA) http://ftacademy.org/sites/ftacademy.org/files/materials/fta-m4-web_development.pdf

Other Technologies
Information Systems: A Manager’s Guide to Harnessing Technology by John Gallaugher http://open.lib.umn.edu/informationsystems/
Software architecture (FTA) http://ftacademy.org/sites/ftacademy.org/files/materials/fta-m11-soft_arch-pre.pdf
Version Control with Subversion by Ben Collins-Sussman, Brian W. Fitzpatrick & C. Michael Pilato http://svnbook.red-bean.com/
Perl Language Reference Manual for Perl version 5.12.1 by Larry Wall and others
How Wikipedia Works by Phoebe Ayers; Charles Matthews; Ben Yates https://archive.org/details/HowWikipediaWorks

Discrete Mathematics
Discrete Mathematics: An Open Introduction – http://discretetext.oscarlevin.com/home.php
Spiral Workbook for Discrete Mathematics – http://open.umn.edu/opentextbooks/BookDetail.aspx?bookId=237
Applied Discrete Structures by Alan Doerr; Kenneth Levasseur v2 (whole book) – /ADS_V2-0.pdf V3 (first 10 chapters) – http://faculty.uml.edu/klevasseur/ads2/
Mathematical Reasoning: Writing and Proof, Version 2.0 – http://scholarworks.gvsu.edu/books/9/