I was given Babywise (the 2001 edition) and being an uninformed, naive mother the book's goal sounded good to me. I was so thrilled when my daughter suddenly started sleeping 8-10, even 12 hours overnight!
She never cried herself to sleep so I really thought everything was okay. She was responding just as the book had said she would. I had, by Ezzo's description, the "perfect" child: the one who easily fell into her feeding schedule and who was sleeping 10+ hours at night. It was picture perfect.
She just cooed and slept and ate.
Then she slept longer and nursed less and then fussed and slept more, and I'd go check the book and ask on message boards and was told I was being a silly new mom -- how lucky I was to have a good sleeper.
Then she became really fussy at feedings, would nurse for an hour at a time, screaming as soon as she unlatched. I tried pumping my milk just to get a break. I got nothing, and by this time my baby was quite weak.
I took her to the hospital where she was diagnosed as FTT ("failure-to-thrive"). She spent three days in hospital. I was told to burn Babywise and that babies should be fed on demand, that breastfeeding was a supply and demand process. The more my daughter fed, the more milk I would produce. They explained to me that this was especially important during the early months when my body was learning when to produce milk but also how much to produce and baby was of course learning to nurse efficiently as well. I was also told most babies naturally put themselves on a flexible schedule when they are old enough. So there is no need to enforce a parent-directed schedule.
The reason why my baby was sleeping so long was her blood sugar was dropping so low she couldn't wake up. She, in fact, was going into a coma. She may have had a pre-existing condition, but following Babywise reduced my milk supply and gave me a false picture of normal, healthy feeding and sleeping patterns, making her health problem truly dangerous. We almost lost our baby.
In the hospital they had me nursing my baby girl every 1.5 hours around the clock, followed by a few ounces of a high-calorie formula. When she was released, I took her to bed with me and for a few more days I just basically attached her to me 24/7 and allowed her to nurse whenever she wanted. Within a few weeks she was a champion nurser and we went on to have a long and satisfying nursing relationship!