Discovered Attack and Discovered Check

This is one of the strongest tactical moves in Chess because the piece which moves away discovering check can inflict maximum damage to the enemy.

See the example below:
White to play wins the Black Queen through Discovered Check:

The below position is from a famous game, often referred to as the Windmill game. Alekhine wins through a beautiful series of Discovered Checks.

Discovered Check on Wiki

Tutorial on Discovered Attack on Chess Corner

The Best example games on Discovered Check on Chess Games

Discovered Check Guide on Chess Game Strategies