Howard Haines Brinton was an author, professor and director whose work influenced the Religious Society of Friends movement for much of the 20th century. His books ranged from Quaker journal anthologies to philosophical and historical dissertations on the faith, establishing him as a prominent commentator on the Society of Friends.
First written in 1942 by the executive director of Pendle Hill at the time, Howard Brinton, this pamphlet is one of the most popular selling titles over the history of the institution's pamphlets, I believe. It was revised in 1950, 1953 and not again until 1993. My copy, which has a 2006 introduction in the reprint, must be based on this final revision.
As a non-member of the Society of Friends, I highly recommend starting here if you've any interest in Quaker thought and practice. Friends, too, over the decades, apparently have found it useful based on the number of reprints and sales.
As a novice in my understanding of anything Quaker, and at the time on the 20th pamphlet along my quest to eventually read them all, I found Brinton's explanation of the "Quaker method" to be the most accessible and inviting of any I'd read yet.
The Quaker "reason for refraining from the formulation and use of creeds is the conviction that no form of words can adequately convey the living, growing truth of the Christian religion. This truth was first fully revealed in a life lived on this Earth. Truth of this kind continues to be revealed in and through life." (p. 13)
They further hold that the New Testament must be read as “a whole text, not individual, isolated excerpts. It is the Spirit of which it was given forth continues to reveal Truth to the human heart. It is only through this Spirit that the whole meaning of the New Testament can be grasped." (p. 13) Like how scientists use the scientific method, "the basis of the test is not facts arrived at, but the method used. Scientists may disagree on facts but they do not disagree on method. Similarly, the Society of Friends accepts into membership a person who is willing to follow the Quaker method regardless of where it may lead." (p. 14) But, just as science is based on the belief that "the universe is a cosmos not a chaos”, the Quaker's method is “based on the belief in a God-centered spiritual universe, the inner truth and meaning of which is in some degree accessible to humankind." (p. 14)
Both scientist and Quaker assume "under the same conditions the same method will produce the same results." And further, both scientist and Quaker accept a certain body of facts based on previous work but it is also subject to revision from future research. (p. 14)
"Worship is central and fundamental in Quaker practice. Out of it, all religious and social exercise is derived." The discovery of silent, unprogrammed worship "was the discovery of Quakerism." It arose not from theory or ideology, but from experience. "The early Friends discovered the Divine Presence in their hearts at a time when current religion consisted largely on the belief in a distant God whose plan of salvation was recorded in a sacred book." (p. 15)
Quakers added one important element to their practice – the direct contact with the Divine Source from which the Truth had sprung the sacred book itself, calling it variously "the light within," and "that of God in everyone" and the "Seed of the Kingdom." For Quakers, "religion could no longer be a matter of words, doctrines, and ritual. It was communion with Divinity itself." (p. 16)
The form of worship then requires no sermon or altar. It requires expectant silence, souls reaching outwards. "The Society of Friends has never issued specific instructions regarding what the worshipper should do during the silence, believing that such instruction would limit the freedom of the Spirit, which, like the wind, ‘bloweth where it listeth’ ((John 3:9).” (p. 17)
No ritual of baptism or communion is needed because these are outward manifestations at best which pale in comparison to that of God within. I'm reminded of a line translated from the Tao Te Ching about "ritual being the husk of true faith."
Too, like the Atman of Hinduism or the eight-fold path of Buddhism , Brinton says the work of the Quaker in active worship requires patience and humility that is rewarded in the dissolution of the individual into understand the larger whole.
"Growth should not be hurried. The slower the growth, the longer-lived the plant. To the surface of the mind with which we meet the world around us, worship adds the dimension of depth. ... Here the longing of the individual worshiper is no longer the center of interest, not because it is wholly eliminated, but because it finds itself transformed by being organically related to a larger whole of life that has no outer limit." (p. 20-21)
I won't quote more, but could. This is worth reading for yourself if you're interested at all in the topic.
The half I read described what some experiences of Quaker Meeting is like, though the author admits that it is pretty impossible to generalize such an experiential religion. I ultimately found it to be too dry and apparently unfinishable. It lived next to my bed for months, but found its way back to the Meetinghouse library half-unread.