If you are new to Montessori and have young children I would suggest you read How to Raise and Amazing Child (Tim Seldin) or Montessori from the Start (Paula Polk Lillard & Lynn Lillard Jessen).
Understanding the Human Being (Silvana Quattrocchi Montanaro) is my absolute bible however I would only recommend it to people who already have some background Montessori knowledge.
But what about Montessori herself? How much Montessori have you read and would you recommend it to parents??
Some say she is hard to read or a little dry. I think it depends on what you are reading. Some of her texts or transcribed speeches/lectures are aimed at health professionals and teachers. Some times I am left wondering what she was going on about or what it really means.
However the best text of hers that I would recommend to all parents is The Absorbent Mind. I was happy that I purchased my own copy because as I started reading I had the compulsion to write, scribble, highlight and dog ear the pages. When I first read it everything else made sense. I enjoyed reading her thoughts in her own words. When you read Montessori it is just you and her and you can interpret her as you like. You can feel her passion and the deep consideration she gave to children.
And it is true, her words are revolutionary.