Can you cast the back face of a double-faced card from your hand?

Double-faced cards (DFCs) have a front face and a back face. By default, you may only cast the front face of a DFC from your hand. The back face is not a castable option while the card is in your hand under normal rules. This is established in CR 711.4, which states that only the front face of a double-faced card can be cast while it is in a zone other than the battlefield.

The back face becomes relevant primarily through the transform or disturb mechanics. Transform causes a permanent already on the battlefield to flip to its back face under specific conditions (CR 701.28). It is not a casting action — it is a state change for a permanent already in play.

There are, however, important exceptions. Some back faces have the keyword ability Disturb (e.g., cards from Innistrad: Midnight Hunt), which explicitly grants permission to cast the back face from your graveyard — not from your hand (CR 702.152a). Similarly, some MDFCs (modal double-faced cards) allow you to cast either face, but these are a distinct card type where both faces are labeled as castable options (CR 711.2). A standard transforming DFC does not grant this permission.

Example: You have Delver of Secrets (a transforming DFC) in your hand. You may cast the front face, Delver of Secrets, for its mana cost. You cannot choose to cast Insectile Aberration (the back face) directly from your hand — it only appears when Delver transforms on the battlefield after meeting its condition.

In summary: for standard transforming DFCs, only the front face is castable from hand. For MDFCs, both faces may be cast from hand per the card's specific rules. Always check whether your DFC is a transforming DFC or an MDFC, as the rules differ significantly.