Summary of the Six Stages

Body Isolation
This stage begins when, having completed the practices of the generation stage, one is finally able to cause the winds to enter, abide, and dissolve into the central channel through the force of meditation.
It is called body isolation because one isolates one's mind from conceiving of the physical world as ordinary, as one has been doing during the generation stage, seeing phenomena as sealed by bliss and emptiness.

Verbal Isolation
This stage begins when the yogi is able to cause the winds to enter, abide, and dissolve in the central channel at the heart. At this stage, the main practice is vajra recitation which releases the various channel knots in preparation for the next stage where the yogi can dissolve the winds into the indestructible drop at the heart.
It is called verbal isolation because one isolates one's mind from the conception that the three phases of the winds are different from the three tones of OM AH HUM.

Mind Isolation
This stage begins when the yogi is able to cause the winds to enter, abide, and dissolve in the indestructible drop. At this stage the use of a seal is necessary: if the yogi uses a wisdom seal then they will only attain mere mind isolation since they will be unable to also dissolve the pervasive wind in the indestructible drop (these yogis will wait for the clear light of death to do this); if the yogi uses an action seal then they will attain final mind isolation and give rise to the example clear light.

It is called mind isolation because one isolates one's mind from conceptuality.

Illusory Body
Having manifested example clear light, the yogi will arise in the impure illusory body, either instead of the intermediate state (if one utilised the clear light of death) or in this very life (if one utilised an action seal).

Clear Light
Eventually the yogi will manifest clear light realising emptiness again, only this time the realisation will be direct rather than conceptual. This is the meaning clear light and the direct antidote to all afflictive obscurations together with their seeds.

Union
When the yogi arises from the meaning clear light the union of abandonment and the pure illusory body are attained simultaneously. The yogi will re-enter meaning clear light and thereby attain the union of realisation. At this stage the yogi will continue to practice until they generate the meaning clear light that is the antidote to the knowledge obscurations and from that point will not longer need to arise out of that meditative equipoise – this is the attainment of non-learner's union, buddhahood.

Up a level: Completion Stage