This is a card sleight by which you can keep the identity of the top card of the pack secret by apparently showing it to your audience – when in fact you are really showing them the second card.
Square the pack up well in the left-hand – it being in the face down position. Next bring the right-hand over the pack with the thumb of the back of the pack and fingers at the far end. Go through the motions of squaring the end of the pack and at the same time make the ends of the pack a little wedge shaped by pressing back with the right-hand fingers. Using the ball of the thumb at the back end of the pack, lever up the ends of the two top cards and slip the left little finger tip underneath.
Now you have the cards in readiness and the audience should not able to see the slightly raised edge of the top two cards at the back of the pack. Using the right-hand thumb on the face of the second card down and the first finger on the back of the top card nearest to you, raise the back end of the top two cards and turn them over revealing the face of the second card down.
As you place them (with the second card face up on the top of the pack on show) you make sure that they are protruding over the inner end of the pack by about 1 cm. At this point you name the card to your audience then grip the two top cards in the same manner as before using the thumb and first finger of the right-hand below and above respectively and you turn the two cards face down on top of the pack flush.
This particular sleight of hand has many different uses, one of the most obvious is that you can apparently show the top card then place it in the middle of the pack and it immediately appears to return to the top.
The double lift sleight of hand is one of the most popular and well established sleights in the whole repertoire of card manipulation. This is proven by the fact that it has been around for well over 200 years. It was first published in 1776! You can read more on Wikipedia’s page.
The great card magician Dai Vernon was known for performing the double turnover – an extension of the double lift sleight of hand.