The Stages of Higher Knowledge (Books Section)

In these essays Steiner describes the experiences of the student of the three higher stages of consciousness: Imagination, Inspiration, and Intuition. He shows how the student progresses through the various stages on the path to higher knowledge. These essays appeared in the magazine Lucifer-Gnosis and are a continuation of Knowledge of the Higher Worlds and Its Attainment.
Link: http://wn.rsarchive.org/Books/GA012/English/AP1967/GA012_index.html

The Threshold of the Spiritual World (Books Section)

In The Threshold of the Spiritual World, Steiner describes various spiritual experiences, thus offering continually fresh points of view on the supersensible world. Here again, Steiner also presents clear suggestions for the reader’s own practice of meditation.
Link: http://wn.rsarchive.org/Books/GA017/English/GPP1922/GA017_index.html

Brunetto Latini (Lectures Section)

In the Lectures Section of the Rudolf Steiner Archive: Brunetto Latini, by Rudolf Steiner.
Link: http://wn.rsarchive.org/Lectures/BruLat_index.html

The Soul’s Probation (Mystery Drama) (Books Section)

Includes The Portal of Initiation, The Soul’s Probation, The Guardian of the Threshold, and The Soul’s Awakening. Steiner’s bold attempt to depict in dramatic form the experiences of a group of people and their relationships as they go on a path of spiritual development as well as the supersensible beings who help and hinder them.
Link: http://wn.rsarchive.org/Books/GA014/English/APC1925/GA014-2_contents.html

Anthroposophical Approach to Medicine (Lectures Section)

In the Lectures Section of the Rudolf Steiner Archive: Anthroposophical Approach to Medicine, by Rudolf Steiner.
Link: http://wn.rsarchive.org/Lectures/GA314/English/APC1951/AnApMe_index.html

The Sermon on the Mount (Lectures Section)

In the Lectures Section of the Rudolf Steiner Archive: The Sermon on the Mount, by Rudolf Steiner.
Link: http://wn.rsarchive.org/Lectures/SerMnt_index.html

Kristusimpulsen i tidens utvikling og dens virke i mennesket (Lectures Section)

In the Lectures Section of the Rudolf Steiner Archive: Kristusimpulsen i tidens utvikling og dens virke i mennesket, by Rudolf Steiner.
Link: http://wn.rsarchive.org/Lectures/KriImp_index.html

The Philosophy of Spiritual Activity (Lindemann) (Books Section)

The Philosophy of Spiritual Activity demonstrates the fact of freedom – the ability to think and act independently – as a possibility for modern consciousness. Read properly, it leads the reader to the experience of presence or living thinking – new thinking – by which all human activity may be renewed.
Link: http://wn.rsarchive.org/Books/GA004/English/AP1986/GA004_index.html

Christianity in Human Evolution (Lectures Section)

Rudolf Steiner Archive Document: Christianity in Human Evolution Christianity in the Evolutionary Course of Mankind Avatar Beings
Link: http://wn.rsarchive.org/Lectures/ChHuEv_index.html

Truth and Knowledge (Books Section)

This work, essentially Steiner’s doctoral dissertation, which is subtitled “Introduction to the Philosophy of Freedom.” is just that: an essential work in the foundations of anthroposophy in which the epistemological foundations of spiritual cognition are clearly and logically laid forth.
Link: http://wn.rsarchive.org/Books/GA003/English/GC1981/GA003_index.html