This is a topic which will probably be outside the experience of all but the most esoterically minded Freemason. Alas, in this day and age, that is the majority. While it may be true that in today's world, Freemasonry does not contain an active system or structure of esoteric education, but that does not mean that Freemasonry does not contain within its symbolism, esoteric teachings.
They are there, whether any given mason or group of masons see them, or even whether they like the idea or not. It is a sad truth about humankind, and Freemasons are no exception, that those who are uncomfortable with the more profound questions of life, or the search for knowledge which challenges their comfortable assumptions that reality can be measured by the limits of their vision, usually seek to deny the right of others to seek a greater vision.
One such visionary was Rudolph Steiner (1861 - 1925). His childhood was spent in the Austrian countryside. At the age of eight Steiner was already aware of things and beings beyond the material. Writing about his early experience, he noted, “[T]he reality of the spiritual world was as certain to me as that of the physical. I felt the need, however, for a sort of justification for this assumption.”
Recognizing his intelligence, his father sent him to the Realschule at Wiener Neustadt, and later to the Technical University in Vienna. Steiner had to support himself, by means of scholarships and tutoring. Studying and mastering much more than was in his curriculum, he always was fascinated by the question of knowledge itself. He was cognizant that in the experience of the personality, one is in the world of the spirit. Although he took part in the arts, sciences, even politics — he felt that “much more vital... was the need to find an answer to the question: How far is it possible to prove that in human thinking real spirit is the agent?”
During the last two decades of the nineteenth century, Steiner published extensively on scientific, literary, and philosophical subjects, including some popular work on Goethe's scientific writings. After the beginning of the 20th century, he transformed his earlier ideas into a methodical research of psychological and spiritual phenomena.
His curiosity led to innovations in medicine, science, education (Waldorf schools), philosophy, religion, economics, agriculture (Bio-Dynamic method), architecture, drama, eurythmy, and other areas. Shortly before his death he founded the Anthroposophical Society.
While many Anthroposophists are as uncomfortable with this aspect of his life and research as Freemasons are to consider him one of their own, Steiner was a Freemason. Indeed, he worked on a combination of Freemasonry and Anthroposophy, and wrote on it, as well as on the related subject of the spiritual insights of Rosicrucianism.
More details about his activities as a Freemason can be found on that excellent website, Four Hares: http://www.fourhares.com/freemasonry/Steiner_and_masonry.html .
Below are links for several books by Steiner on Freemasonry, and about Steiner and Freemasonry. I hope those masons with a desire for more light will explore this fascinating work.
The majority of his lectures on Freemasonry are to be found in The Temple Legend. His ritual work has been reprinted in Freemasonry and Ritual Work: The Misraim Service. Also of interest to Freemasons are Rosicrucian Wisdom: An Introduction, The Secret Stream: Christian Rosenkreutz and Rosicrucianism, and Knights Templar: The Mystery of the Warrior Monks. While this last title might seem an unlikely addition to a bibliography of Steiner's work relating to Freemasonry, I include it because, as far from the normative views on the subject, his chapters on Jakim and Boaz in this book,provide an interesting contrast to the usual interpretations of those symbols. So, I would suggest that if you are intrigued by Steiner's relationship to Freemasonry, you might also wish to take a look at The Seer's Handbook.