Center participants sometimes ask for descriptions of Nondualism. Below is from
Wikipedia. I hope you find it useful. You might like to print this so you can read it from time to time.
In loving service,
(From Wikipedia, the free encyclopedia)
Nondualism implies that things appear distinct while not being separate. The word's origin is the Latin duo meaning "two" and is used as the English translation of the Sanskrit term advaita. The term can refer to a belief, condition, theory, practice, or quality.
Nondualism may be viewed as the understanding or belief that dualism or dichotomy are illusory phenomena. Examples of dualisms includeself/other, mind/body, male/female, good/evil, active/passive, dualism/nondualism and many others. It is accessible as a belief, theory, condition, as part of a tradition, as a practice, or as the quality of union with reality.
A nondual philosophical or religious perspective or theory maintains that there is no fundamental distinction between mind and matter, or that the entire phenomenological world is an illusion (with reality being described variously as the Void, the Is, Emptiness, the mind of God, Atman or Brahman). Nontheism provides related conceptual and philosophical information.
Many traditions (generally originating in Asia) state that the true condition or nature of reality is nondualistic, and that these dichotomies are either unreal or (at best) inaccurate conveniences. While attitudes towards the experience of duality and self may vary, nondual traditions converge on the view that the ego, or sense of personal being, doer-ship and control, is ultimately said to be an illusion. As such many nondual traditions have significant overlap with mysticism.
Nondualism may also be viewed as a practice, namely the practice of self-inquiry into one's own being as set forth by Ramana Maharshi, which is intended to lead a person to realize the nondual nature of existence.
Nondualism can refer to one of two types of quality. One is the quality of union with reality, God, the Absolute. This quality is knowable and can be gained spontaneously and via practice of inquiry. A second quality is absolute by nature, or to put it in words, "conceptual absence of 'neither Yes nor No'," as Wei Wu Wei wrote. This latter quality is beyond the quality of union. It may be viewed as unknowable.
Accessibility is not relevant to the second quality mentioned in the paragraph above, since, according to that quality, an essential part of its gaining includes the realisation that the entire apparent existence of the individual who would gain access to understanding nondualism is in fact merely illusional. Achieving the second of these qualities therefore implies the extinguishing of the ego-sense that was seeking it:
"What is the significance of the statement 'No one can get enlightenment"? ... Enlightenment is the annihilation of the 'one' who 'wants' enlightenment. If there is enlightenment ... it means that the 'one' [ie individual ego] who had earlier wanted enlightenment has been annihilated. So no 'one' can achieve enlightenment, and therefore no 'one' can enjoy enlightenment. [...] if you get [a] million dollars then there will be someone [an ego-sense] to enjoy that million dollars. But if you go after enlightenment and enlightenment happens, there will be no 'one' [ie, no individual ego-sense] to enjoy enlightenment." 
NONDUALISM VERSUS MONISM
The Western philosophical concept monism is similar to nondualism. Some forms of monism hold that all phenomena are actually of the same substance. Other forms of monism including attributive monism and idealism are similar concepts to nondualism. Nondualism proper holds that different phenomena are inseparable or that there is no hard line between them, but that they are not the same. The distinction between these two types of views is considered critical in Zen, Madhyamika, and Dzogchen, all of which are nondualisms proper. Some later philosophical approaches also attempt to undermine traditional dichotomies, with the view they are fundamentally invalid or inaccurate. For example, one typical form of deconstruction is the critique of binary oppositions within a text while problematization questions the context or situation in which concepts such as dualisms occur.
To the Nondualist, reality is ultimately neither physical nor mental. Instead, it is an ineffable state or realization. This ultimate reality can be called "Spirit" (Sri Aurobindo), "Brahman" (Shankara), "God", "Shunyata" (Emptiness), "The All" (Plotinus), "The Self" (Ramana Maharshi), "The Dao" (Lao Zi), "The Absolute" (Schelling) or simply "The Nondual" (F. H. Bradley). Ram Dass calls it the "third plane"any phrase will be insufficient, he maintains, so any phrase will do. The theory of Sri Aurobindo has been described as Integral advaita.
It should be pointed out that technically, there can be no such thing as a nondual perspective or theory or experience, only a realization ofOneness or nonduality. One cannot accurately claim to experience nonduality, because the concept of experience depends on the subject-object distinction, which is a duality. The subject experiences an object, which is something separate from the subject. This is incompatible with a truly nondual realization. Thus, technically, there cannot truly be an accurate verbal account of this union, only words that insufficiently point to the realization.
KEN WILBER comments that nondual traditions:
"...are more interested in pointing out the Nondual state of Suchness, which is not a discreet state of awareness but the ground or empty condition of all states... [They] have an enormous number of these 'pointing out instructions', where they simply point out what is already happening in your awareness, anyway. Every experience you have is already nondual, whether you realize it or not. So it is not necessary for you to change your state of consciousness in order to discover this nonduality. Any state of consciousness you have will do just fine, because nonduality is fully present in each state... recognition is the point. Recognition of what always already is the case. Change of state is useless, a distraction... subject and object are actually one and you simply need to recognize this... you already have everything in consciousness that is required. You are looking right at the answer... but you don't recognize [it]. Someone comes along and points [it] out, and you slap your head and say, Yes I was looking right at it..."
NISARGADATTA MAHARAJ when asked how to tell when someone is approaching this understanding, commented:
"Even then it is a concept again. But I give you a criterion by which one can sort of judge something. When a stage is reached that one feels deeply that whatever is being done is happening and one has not got anything to do with it, then it becomes such a deep conviction that whatever is happening is not happening really. And that whatever seems to be happening is also an illusion. That may be final. In other words, totally apart from whatever seems to be happening, when one stops thinking that one is living, and gets the feeling that one is being lived, that whatever one is doing one is not doing but one is made to do, then that is a sort of criterion."