1. It is Science
The Philosophy Of Freedom is not philosophy as such, but rather a description of Rudolf Steiner's experiences on the way to freedom. It does not give a definition of freedom that we merely memorize, but points to a place where freedom originates --the conceptual realm of universal concepts-- where free thinking, pure and unbiased, can be experienced.
“What I was really trying to do in The Philosophy of Freedom, was to locate freedom empirically, and thus put it on a solidly scientific basis.”
2. It is Freedom
Moral freedom is achieved when we bridge the gap between our perceptible unfree nature (built up by nature, society and religion) and the concept of free individuality (ethical individualism) through the course of one's development with the expression of our ideals in life. To become a free individuality we need to have a clear understanding of what free individuality is. POF 9-11
True freedom is only achieved when knowledge and morality are united. (morality informed by knowledge) POF 10-1918 Addition
3. It is Thought Training
The book is intentionally composed in a certain way to broaden and deepen the readers thinking. Each chapter expresses a variety of views leaving the reader free to arrive at their own conclusions. It is independent thinking so we cannot rely on familiar terms and images but must instead make an effort to “intuitively” grasp the universal concepts pointed to by the words. This training in the realm of universal thought is the thought training required to attain freedom.
“The primary purpose of my book is to serve as thought training, training in the sense that the special way of both thinking and entertaining these thoughts is such as to bring the soul life of the reader into motion in somewhat the way that gymnasts exercise their limbs.”
“A personal God is nothing but a human being transplanted into a Beyond.”
5. It is not Anthroposophy
Near the end of his life, Steiner suggested that The Philosophy of Freedom would outlive all his other works. It stands on its own completely independent of his later spiritual research and organizations,
“You will find nothing at all in The Philosophy of Freedom that is derived from clairvoyant communications of spiritual science.”
“this book occupies a position completely independent of my writings on actual spiritual scientific matters... What I have said in this book may be acceptable even to some who, for reasons of their own, refuse to have anything to do with the results of my researches into the spiritual realm.” POF, 1918 Preface to the Revised Edition
"The first thing that my contemporaries found unpalatable in my book The Philosophy of Freedom was this: they would have to be prepared first of all to fight their way through to a knowledge of freedom by self-disciplined thinking." If you don't know what freedom is you will be unable to realize freedom because freedom is not an inborn idea, the idea of freedom must first be gained and understood before it can be realized by incorporating it into your life. Since this is a science of freedom it applies to everyone just like global warming does whether you believe in it or not. Steiner's concept of freedom can be found in other sources, a piece discussed here and another part there. All the ideas in POF are discussed elsewhere, separately. After finding the pieces you will still need to fit them together properly. Within POF you find the full concept of freedom with all the parts organized into a whole, but you still have to fight to understand it. You have a good chance if you know nothing of anthroposophy.
The greatest barrier to understanding POF are the revisions, omissions and explanations of anthroposophists. It really is a scandal. If you began with the original version and had no other reference than Steiner's pre-theosophy work (pre-1900) most wouldn't have a problem. Every truth I get is a correction of an anthroposophy misunderstanding about POF. There misleading translations and misdirecting summaries have set me back a decade. The book can be won through simple reading comprehension if you work with the original 1916 Hoernle edition. That translation still needs basic translation cleaning up and will be done some day.
Anthroposophists distort POF to fit their theory of clairvoyance that for some reason none of them seem to ever achieve (except Steiner, but he was born with it). The science of freedom is not compatible with the vague mysticism of spiritual clairvoyance. A great example of the clarity of the original version is the beginning of Chapter 9 in the original Hoernle edition that explains the relation between ones Conceptual System and Knowledge & Action. Most of this was deleted in the other editions.
9. THE IDEA OF FREEDOM
 THE concept "tree" is conditioned for our knowledge by the percept "tree." There is only one determinate concept which I can select from the general system of concepts and apply to a given percept. The connection of concept and percept is mediately and objectively determined by thought in conformity with the percept. The connection between a percept and its concept is recognized after the act of perception, but the relevance of the one to the other is determined by the character of each.
 In willing the situation is different. The percept is here the content of my existence as an individual, whereas the concept is the universal element in me. What is brought into ideal relation to the external world by means of the concept, is an immediate experience of my own, a percept of my Self. More precisely, it is a percept of my Self as active, as producing effects on the external world. In apprehending my own acts of will, I connect a concept with a corresponding percept, viz., with the particular volition. In other words, by an act of thought I link up my individual faculty (my will) with the universal world-process. The content of a concept corresponding to an external percept appearing within the field of my experience, is given through intuition. Intuition is the source for the content of my whole conceptual system. The percept shows me only which concept I have to apply, in any given instance, out of the aggregate of my intuitions. The content of a concept is, indeed, conditioned by the percept, but it is not produced by it. On the contrary, it is intuitively given and connected with the percept by an act of thought. The same is true of the conceptual content of an act of will which is just as little capable of being deduced from this act. It is got by intuition.
 If now the conceptual intuition (ideal content) of my act of will occurs before the corresponding percept, then the content of what I do is determined by my ideas. The reason why I select from the number of possible intuitions just this special one, cannot be sought in an object of perception, but is to be found rather in the purely ideal interdependence of the members of my system of concepts. In other words, the determining factors for my will are to be found, not in the perceptual, but only in the conceptual world. My will is determined by my idea.
The conceptual system which corresponds to the external world is conditioned by this external world. We must determine from the percept itself what concept corresponds to it; and how, in turn, this concept will fit in with the rest of my system of ideas, depends on its intuitive content. The percept thus conditions directly its concept and, thereby, indirectly also its place in the conceptual system of my world. But the ideal content of an act of will, which is drawn from the conceptual system and which precedes the act of will, is determined only by the conceptual system itself.
An act of will which depends on nothing but this ideal content must itself be regarded as ideal, that is, as determined by an idea. This does not imply, of course, that all acts of will are determined only by ideas. All factors which determine the human individual have an influence on his will.