Educational research

Educational research investigates how people learn. Literacy was the first starting-point. Before about 1470 all books were hand-written. Printing made the word visible. Before 1800 most ordinary people could not read or write. That was true for all countries. By 1900 most people in the most industrial countries could read. The Bible was one of the causes: people wanted to read the Bible in Christian countries. Just as important was industrialization. With industry grew a need for instruction, and there were printed rule books in key industries such as the railways. Church registers in England show increasing literacy as judged by the ability of men to sign their names. Previously, if a man signed with an X, a church clerk added his name.
An enormous amount of research has been done in the United States, and very much less elsewhere
Researching comes in many ways. Researches here focuses more on how people gather new things into their minds. These people could be learners or teachers. Both can interact in spaces of learning. These spaces are also known as classrooms. So researchers collect data inside classrooms, more or less. 
Educational researchers believe that the way they do research must be careful and well-ordered. First is on the basis of comparison. Second is on principles to set that everyone follows. Third is on how researchers do their research. Also, they borrow concepts from other studies, may it be about minds, society, human beings, and reasoning. The same goes for how they do their research.
Textbooks.
There have been many attempts to bring together the skills and the knowledge needed by teachers. The following (mostly multi-author) books are examples.
AERA journals and publications.
The American Educational Research Association publishes many journals on teaching.