Came across this wonderful book ThinkOS.
Later moved to https://github.com/AllenDowney
then to http://allendowney.com/
then to https://greenteapress.com
then to their manifesto: http://greenteapress.com/wp/textbook-manifesto/
His manifesto:
Students should read and understand textbooks.
and many more..
over all this book is too good.