(Uncommon - Weatherlight. , Return target instant, interrupt, or sorcery card from your graveyard to your hand.)

I must admit that I think Relearn is one of the most useful blue cards to come down the line in a long time. Any spell that allows you to take any instant, interrupt or sorcery out of your graveyard and put it into your hand is fantastically useful for any color, but especially for blue.

The range of spells that Relearn can recover from your graveyard makes it incredibly flexible. Want to bring back that Time Walk? How about that Abeyance? I use Relearn to keep the number of cards in my decks manageable. Playing white and blue like I do, I feel a bit insecure if my decks don't have four Counterspells, but with Relearn I can go with two Counterspells rather than four and keep the deck small. Go with two Counterspells, a Dissipate and an Interdict with a Relearn rather than two or three of each and you can go with more creatures or artifacts in a smaller deck without compromising your defenses or your control.

I have found that Relearn also helps you in the event that you play a Counterspell and then find that you should have saved it for an even nastier spell your opponent is trying to get out. Relearn actually gives you the chance to recover from mistakes, a rarity in Magic. I have used Relearn to recover Interdicts, Braingeysers, Jumps, and any number of useful instants, interrupts and sorceries. Frequently I have used Relearn to recover crucial spells for combos and cast them again. Updraft cast once on an Elder Land Wurm is a fun surprise to spring on an opponent, but to cast the Updraft a second time after Relearn-ing it is guaranteed to make said opponent take time out to climb the walls. Magical Hacks are good candidates for Relearn-ing, as well as Reverse Damage, and Miraculous Recovery. If you have ever said to yourself, "I wish I had another (instant, interrupt or sorcery) to play", and I know I have, then Relearn is for you.
—Helva