The pitching wedge is a versatile golf club that you can use for full shots -- usually less than 100 yards -- and close approach shots and chips. Although not typically used in the sand, the pitching wedge can be the club of choice for long bunker shots.
The loft of a pitching wedge varies according to the manufacturer and the model of the club. Typically, pitching wedges have a loft between 46 and 50 degrees, although 46 to 47 degrees is most common. It's occasionally possible to find a pitching wedge with a loft as low as 45 degrees.
The pitching wedge fits in place between your 9-iron and gap wedge or sand wedge. If the 9-iron is too long for your approach shot, the pitching wedge is your next logical option. Gap wedges, sand wedges and loft wedges, in this order, have steeper lofts to allow you to elevate the ball more with less overall distance.
For someone learning to golf, a pitching wedge is typically the only wedge he will need until he gets used to the short game. The pitching wedge, though, is not as effective for sand shots, so the sand wedge would be the next logical addition to the new golfer's bag.
Regardless of your level of skill, the pitching wedge is a club that you will likely use throughout the round. If you use the wedge that came with your irons, it's an easy transition because the club has the same appearance and style of grip.