If we cannot remain present during sleep, if we lose ourselves every night, what chance do we have to be aware when death comes? If we enter our dreams and interact with the mind's images as if they are real, we should not expect to be free in the state after death. Look to your experience in dreams to know how you will fare in death. Look to your experience of sleep to discover whether or not you are truly awake.

The Tibetan Yogas of Dream and Sleep (ed. 2004)