Reverie, or trance, was the Elven state of meditation, which had certain sleep-like effects. During this state of meditation, elves conducted a series of mental exercises that refreshed their bodies and minds. During this meditation, elves were aware of the outside world, though breaking meditation in response to external events had an effect similar to disturbing the sleep of any other Mortalborn.
When elves entered this state, they vividly relived past memories, both pleasant and painful. As all true elves were reincarnations of past selves, it was thought that these dreams were memories of their past incarnations. Like the dreaming of Humans, elves had no control over which memories rose to the fore when they relinquished their bodies to reverie. Most of these memories were sharp and true-to-life, but elves would also occasionally encounter dream-like, prophetic memories in reverie. Crossborn elves could not enter reverie, though their dreams were typically far more vivid than other humanoids.
Though elves were highly resistant to magical sleep effects and similar Spellcraft, this did not mean that they were physically unable to sleep. Elves were sometimes able to sleep if they desired, though they almost always rested in a state of reverie, which took half the time for the same benefits of sleep and also acted as a memory tool. As such, elves very rarely slept, and usually only did so when they were severely ill, wounded, or exhausted. It was thought that the ability for elves to go into reverie, instead of sleep, was the explanation as to why they could shrug off magical sleep-like effects.