concept of links: satellite image over Italy, blended with sphere of networked circles


6 Sites For Free Alternative Textbooks

(Excerpt from: Info from UW News – Posted by Erik Geiger on August 27, 2018)

[…] Engineers, and other STEM majors will want to check out MIT Open Courseware.

Open Culture

Free textbooks (aka open textbooks) written by knowledgable scholars are a relatively new phenomenon. Open Culture offers 200 Free Textbooks.

MIT Open Courseware

MIT OpenCourseWare is a web-based publication of virtually all MIT course content. OCW is open and available to the world and is a permanent MIT activity.

Textbook Revolution

Textbook Revolution is a student-run site dedicated to increasing the use of free educational materials by teachers and professors.


Wikibooks is an open-content textbooks collection that anyone can edit.

Project Gutenberg

Project Gutenberg offers over 56,000 free, public domain eBooks in multiple formats. Topics include English and international literature, foreign languages, history, mathematics, and language instruction.


OpenStax offers peer reviewed, open source textbooks are written by professional content developers who are experts in their fields.


Cheat sheets can be useful as a memory back-up. When I learned Latin, it was stressed that before looking into the lexicon, one should first try to retrieve the information from memory first. It may be there. Then, if needed, look into cheat sheet, which can sometimes be a challenge too given the information concentration. Cheat sheets come in various formats, which can sometimes be called quick reference guide instead.

Molecular graphics

RStudio / R

RStudio provides a large series of cheat sheets that encompass a wide range of subjects. The page is located at and covers R, python, R markdown and many specific R packages.


(Note: These are from web site that offers further cheatsheets that are more relevant to web development such as JavaScript, PHP or HTML.)