Reading Steiner

Reading Steiner refers to Rintarou Okabe's ability to, even after switching World Lines, retain his memory of events that have occurred before (from his point of view) the switch.

While no other members of the cast have this immediate knowledge of a switch having occurred or any recollection of what happens in another World Line, they seem to regain some memories occasionally.

For example, Faris remembers sending the D-Mail that prevented her Father's death after talking to Okabe in her Apartment, and Mayuri, visiting her grandmother's grave in the Alpha timeline, speaks of "Nightmares" in which she dies in a multitude of ways.

The ability plays a major role in the plot, most prominently in allowing Okabe to undo the changes caused by the D-Mails and not losing track after each switch.

Trivia

 * The manifestation of Reading Steiner on other people, particularly on Mayuri and Kurisu, appears to be an important plot point in the upcoming movie Steins;Gate: Fuka Ryouiki no Deja Vu.