We were having such a hard time getting DS to sleep in his crib. I always said I would never CIO, but I was getting desperate! Not sure exactly what this is called, maybe Ferber, or modified Ferber, but it worked like a charm. We let him cry 5 minutes, then went in and calmed him down, then let him cry 10 minutes, and that's all we had to do! After 4 nights he didn't even cry anymore. He just laid down in the crib and went to sleep! And he sleeps all night. I am still amazed that it worked. But sooooo relieved! I am actually getting some sleep now.