We have just transitioned our 4 month old from sleeping in bed with me to sleeping in his own crib.  It has been very challenging but he has been sleeping on his own.  However, when he first falls asleep at night he only sleeps up to 1 hour before he wakes up crying.  This often happens the first 2 times he falls asleep.  Later on he will sleep 5 or 6 hours straight so I don't know why he won't do that earlier in the night.  Anyone have any tips/suggestions?