The little girl knew something was wrong. As she came home from school, the sight of police cars around the house alarmed her. The intense voices of her parents arguing frightened her.

The truth would scar her for life. Her father was a paedophile.

Enter a teacher, who took the hand of this young soul and patiently walked her through the trauma, leading her to healing and wholeness. That girl, now a young woman, found the strength to submit her story, in honour of that teacher-healer, for the Great South African Teachers book.

This is not a book about failing schools, troubled children or bad teachers. It is a collection of stories from current and former school children who celebrate the outstanding South African teachers who transformed their lives. From affluent schools and poor, from former-white schools and still-black schools, from the big cities and the small villages, come powerful stories about great educators.

They are great in different ways. There are the subject artists who dazzle young minds with their teaching craft. There are the life performers who help children make the connection between classroom learning and preparation for life. There are the extended parents who care not only for the minds of children but for their hearts as well - these are the "extra-mile" teachers who take on pastoral duties of care beyond their job descriptions. The courageous activist stories tell of teachers who risked their jobs to teach outside the official curriculum during the years of apartheid education. The words and actions of the inspiring mentors have remained with their students long after they left school.

Great teachers have one thing in common: they leave an indelible imprint on the lives of young people.

The book started with a simple invitation in the Sunday Times: "Submit a story about the teacher who made the greatest impact on your life." Within days, scores of stories flooded in - it seemed people had been waiting a long time for the chance to share their memories of educators who changed their lives. This was an idea whose time had come. The stories came from every province: about young teachers and older teachers; from the World War2 era to recent months; from children still in school to octogenarians; about tough-love teachers and gentle, gracious teachers; about teachers of subjects inside school and teachers of life outside school. The rich mix of class, colour and creed in the stories entranced the review panel and the editorial team.

Of all the books I have written or compiled (this one was done with two of my undergraduate students), I cannot think of a more challenging and fulfilling project.

Challenging, because the book raises awkward questions. Is it possible, for example, that there once was a golden era of schooling in South Africa - during the apartheid years? Forget, for a moment, the turbulence outside and the curriculum restrictions inside the schools, and you get the distinct impression that many township schools during those dark years were places of great productivity where dedicated teachers and committed principals made sure children were not short-changed in the learning process.

The tunnel-vision view of the past as one of constant pupil uprisings is perhaps misleading. Even in those difficult years in the apartheid time and space, many teachers understood the dangers of "liberation now, education later". They worked to prepare young people to transform their lives and their communities. The products of those teachers return to centre stage in this book - and what they tell, challenges our stereotyped notions of the past.

The work on the book was fulfilling for me because we have become so exhausted, even overwhelmed, by stories of dereliction and defeat in schools. We are tired of results that show our children can't read and write at the grade level. We worry about young men who drop out of school into all kinds of trouble. We become angry when we cannot relate huge governmental expenditure on schools to minimal results.

We often blame teachers.

Great South African Teachers will lift your spirits with the simple message: though resources matter, dedicated teachers matter more. As the stories show, there is a reason teachers constitute the largest slice of national budgets - they are our most important learning resource.

The book speaks to more than one audience. It can restore some faith in schooling among the public - showing that there is hope, from the past and in the present, and that such hope is founded on the pillars of education: good teachers. It can be an invaluable resource for student teachers by showing which qualities in teachers have a positive influence on learning and living. It can inform school governing bodies of the appropriate criteria to use in teacher recruitment, selection and appointment. It can help the national government be courageous enough to develop a teacher education policy based, not on abstract ideas about what constitutes a good teacher, but on first-person accounts of what the learners themselves see as important qualities in their instructors.

We hope that Great South African Teachers will convey the message that teaching is a career that, for thousands of teachers, remains the most meaningful thing they have ever done. It is important for parents to be reminded that the foundations of democracy and decency are built in these critical years by dedicated teachers. It is important for all of us to remember that it is thanks to the work of heroic teachers that we are able to enjoy the quality and spread of leaders that we have in business, education, health, social welfare and, yes, even in parts of government. When I read these teacher stories, it is a great source of satisfaction to hear where great leaders now find themselves in our democracy. It is important for undecided youth to know, through these stories, that teaching is a calling that many choose not because of the material wellbeing they can attain, but because of the social wellbeing they can impart to pupils and society. Many of the great teachers in this book had options. But they chose teaching because they could make a difference.

With Great South African Teachers we celebrate these teachers in the knowledge that there are many thousands more who make the crucial difference between hope and despair in the lives of 12-million school children in South Africa.

• Jansen is the vice-chancellor of the University of the Free State. He has earned a formidable reputation for transformation and his deep commitment to reconciliation in communities living with the heritage of apartheid. His new book costs R190 and is available at all good bookstores.