My puppy was doing well--until he stopped. Now he cries every time I leave:

Chances are you went too far, too fast. Wait for a break in the crying before going back in. One he's re-engaged with his chew toys or settled down, take another much shorter break from the room.

At your next alone time training, begin with a length of time you know your puppy handles easily and practice at that level for several sessions. Once he's got that down, gradually add on just a bit at a time, stopping just short of when he becomes anxious.

My puppy works himself into a frenzy when I leave him alone.

This may well be a normal puppy reaction to your absence--they can kick up an amazing mini-storm when they're first left alone. You might also be surprised by how long it takes him to get to a break in his vocalizing--5 or 10 minutes is normal, but it can seem like an eternity when it's your baby howling and shrieking.

Many dogs will paw or chew on the kennel door in an attempt to come to you, but stop when it's clear it won't be successful.

These behaviors, upsetting though they may be, are to be expected when you're first starting this type of training. Follow the above steps, make sure you don't keep your puppy in his crate for too long, and make sure the toys you give him when you leave are well stuffed and beloved.

Symptoms your dog may have separation anxiety, and need a dog trainer's help:

* He's not eating food or treats left out while you're away

* Destructive chewing, scratching, or clawing at exit routes--doorways, windowpanes, or the kennel door. If your dog's nails, pads, or teeth are worn down or bloody, or he's panting from exhaustion, he's suffering real separation anxiety.

* Pacing, whining, drooling, and following you closely when you're getting ready to leave