There are many aspects of the Ageless wisdom teachings, and many “schools” of teachings. Generally, I am calling it all “theosophy” (with a small “t” unless it begins a sentence or is part of core teachings of the TS – the Theosophical Society.
Before the foundation of the TS, there were various masonic groups, and a few esoteric and alchemical groups, mostly veiled in mystery and closed to outsiders, and also some scholars who studied Hindu, Buddhist and Islamic texts, mostly mis-understanding them. The Theosophical Society was founded in 1875 under the leadership of Madame Blavatsky (HPB for short) (link to start of history). I highly recommend the biography of her by Gary Lachman, which gives a fair and unbiased description of her life and influence
Her main work was the Secret Doctrine, which brought to the West many teachings from the Eastern religions, and gives out several new teachings derived from the ancient wisdom, such as the “Stanzas of Dzyan”. However, it is not an easy book to follow, and she is very quarrelsome towards people who she disagrees with (and unfortunately she seems to have also bequeathed this tendency to the TS), and much of what she reveals is in fact “veiled” anyway. However, many students find enormous value in this and in her other volumes of collected writings. There is an emphasis on cosmogenesis ( how the universe was created) and anthropogenesis (how mankind came about on earth), and this work and the TS originally gave an impulse towards a search for enlightenment and cosmic consciousness, which now seems out-dated.
I have written an article about the offshoots of the original TS, and also about the changes in the world that can be credited to the TS, which has been surprisingly influential, especially if we include the New Age as being based on the original theosophical impulse. In the TS itself, there have been a number of outstanding teachers who have continued HPB’s work, such as Annie Besant, CW Leadbetter and Geoffrey Hodson. These popularised theosophy in the early years of the 20th Century, particularly the concept of “thoughtforms” which was very influential on modernist artists such as Kandinsky, Mondrian, Klee and Schoenberg (and thus on the Bauhaus movement, etc.). Krishnamurti was also originally connected with the TS
The TS is less influential nowadays, tending to be relatively theoretical and speculative, and less focussed on the experiential efforts and techniques than more recent movements. However, it has had great successes among its membership too – the mental approach clearly works well for some people. I personally can’t get much of a tune out of the main teachings, but, there is a CD available for about £30 of all the main works of the TS, and this is searchable – I used it to find all mentions of fossils and evolution for my article on “Evolution in theosophy”
However, I include a number of "theosophical teachings" that I have found useful !
The Alice A Bailey books were produced from 1919 to 49, and provide in part a commentary on the Secret Doctrine, and also a training and instructions in discipleship, and an introduction to the seven rays. I give an introduction to some of the main concepts in the books.
The Agni Yoga books were written at about the same time, and I provide some brief comments on the Agni Yoga books "Heart" and "Brotherhood" - although these books are not easy to grasp, the ideas in them are seldom dealt with in depth elsewhere.
In general, I have provided some articles which readers might find interesting, and which describe some of the more interesting and practical elements of the modern esoteric teachings.