A modern dog crate is a cage made of wire, wicker, soft-sided material, or molded plastic some of which are foldable, some have three doors, and you can add a cover and bed to some also.
Its purpose is to provide confinement for reasons of security, safety, housebreaking, protection of household goods, travel or illness.
You may think that putting your pet in a crate is mean or inhumane and might cause your pet to resent you or to feel abandoned.
However, dogs view the world differently than people.
As your dog sees it, the crate is a room of his very own - a "safety zone".
The crate helps to satisfy the "cave instinct" inherited from his cave-dwelling ancestors and relatives.
Your dog will feel secure once accustomed to his crate.
The crate can help you achieve a better relationship with your dog by preventing unwanted behavior when you aren't available to supervise him.
The advantages of crate training With the help of a crate

• You can enjoy peace of mind when leaving your dog alone, knowing that nothing can be soiled or destroyed and that he is comfortable, safe, and not developing bad habits.
  
• You can housebreak your pet quickly by using the close confinement to motivate your pet to wait until taken outside, since canines naturally avoid soiling their sleeping area.
  
• You can travel with your dog without risk of the him getting loose and becoming lost or interfering with safe driving.
  And he may be quieter and more relaxed in a crate as he will feel protectedand less inclined to bark.
  
• Your dog can enjoy the security and privacy of a crate of his own to which he can retreat when tired or stressed.
  
• Your dog can avoid much of the fear and confusion caused by your reaction to problem behavior.
  
• Since he can more easily adapt to staying in unfamiliar places as long as he has his familiar "safety zone" along, your pet can be included in family outings, instead of being left behind alone.
  

Buying a crate Look for a wire crate that includes a removable metal floor pan.
Plastic crates can also be used, although some dogs will chew the plastic.
For your pet's comfort, look for one with a smooth floor, or you can add a crate bed for more comfort.
Purchase a crate large enough for your pet to stretch out on its side and to sit or stand erect.
If you have a puppy, it is more economical to buy a wire crate that will accommodate him as an adult, then partition it to the right size.
A movable wire or pegboard partition can be made or purchased.
Too large a crate can undermine housebreaking because your pet may eliminate at one end of the crate and lie down at the other.
Depending on size and construction, a new crate may cost $40 - 250.
This is a bargain compared to the cost of replacing a sofa, woodwork, or carpeting.
Where's the best place for the crate? Dogs are social animals.
Place the crate in an area where the family spends a lot of time - kitchen, family room, living room, etc.
The top of the crate can serve as extra shelf or table space.
At night, move your puppy's crate into your bedroom so you can hear him if he needs to go out.
Will the crate work for all pets? Unfortunately, no.
There are some animals (usually adults) that can't or will not tolerate this form of confinement.
A few will show no desire to keep the crate clean.
By crate training, you are doing your pet a real favor by preventing him from getting into trouble when left unsupervised.