What is the importance of history in education studies?

I am going to assume that you are asking about why the history of education is important within the discipline of education.  The history of any discipline is important, but when it comes to education, it is even more so because the future of any country lies in its education. When we understand the history of education, it allows us to make better judgements, to succeed where previous philosophies and endeavors have failed and to capitalize on the historical successes, too. In other words, we learn from our failures and our triumphs.

To give just one powerful example, historically the education of children with disabilities, to the degree they were educated at all, was to isolate them, often without the amenities that other children had. I remember that when I was in elementary school, "special ed" classes were held in the basement, next to the boiler room. We knew these children were different and perceived them to be somehow inferior to us. This was how it was, not all that long ago, really. And we have learned from our knowledge of this history what a dreadful mistake this was educationally.

On the other hand, we have John Dewey, who was thinking and writing about education over a hundred years ago. His ideas on hands-on learning are just as fresh and important today as they were when he wrote them.  Trends have come and gone in education, but John Dewey is not simply a historical footnote.  His thoughts are of vital importance today in every classroom.

Looking back, there was a time when schools were racially segregated. It was not until 1955 that the Supreme Court held this to be unconstitutional.  As we review this history, it teaches us how damaging segregated education was, for all children, and we have been working ever since on how to provide for educational integration. 

Another valuable aspect of educational history is the history of its aims. Historically, universal education was intended to mold students into good citizens who could participate intelligently in a democracy. Today, it appears that society's aim is to see to it that people have the requisite skills for employment.  That is not necessarily a bad aim, but revisiting the history of previous goals should give us pause, I think, to consider our present priorities. If everyone has a job but is ill-prepared to vote thoughtfully and intelligently and to participate fully in a democratic society, it is my believe that education has failed and that democracy fails as well.  

History shows us where we have been, and the history of education has important lessons to teach us, about what has been done well and what has been done horribly.  We can use our historical knowledge to go forward as much better educators.