We have a 12 month old who is not sleeping through the night. We have tried it all. CIO (Ferber method), Modified cry it out, gradual withdrawal, healthy sleeper/happy baby. I finally picked up the abay whisperer. This is the fourth book I am reading. ANyway, the CIO method was torture. It went against everything I believed I should be doing but I felt forced into it. It took about two weeks to get him to go to sleep on his own and he still woke frequently. He would scream for 1-2 hours when he woke up during the night. It just didn't work for us. However, we have friends who used it with good results. It just didn't work for our personalities, the babies personality, and our parenting style. I think you need to find what works for your family.
Anne