I will answer your question as it relates to the U.S. since you did nt state what country you were inquring about.
Since religion was very important in the early years of America (think Puritans and Pilgrims and Quakers, etc.), children mainly encountered reading materials in the forms of the Bible and in school primers, which were like textbooks students have now. Children learned to read via their parents and/or at school (IF they were lucky enough to be able to attend school). Printed literature was scarce (except in the form of the Bible, of course) until the onset of newspapers and "magazines", which gathered much popularity in later years and contributed to more literacy.