C.
I agree that the Healthy Sleep Habits, Happy Baby book by Weissbluth is EXCELLENT!! I'd say 2 things. Swaddle him as tight as you can (I know it's hard at 4 months) if he's still sleeping on his back. Simply put, this is because they sleep better when they feel cozy and secure. Sleeping on the back makes it more likely that they will startle themselves awake and it's not a natural feel of security...as their front is against you or cuddled up when being held, so they feel comforted like that when sleeping. And schedule...you didn't say what the schedule you've tried is. With a developmentally appropriate schedule, your baby will surely get restful sleep, as it trains the baby to get quality sleep so they are not overtired when trying to sleep. Keep in mind that sleep while being held does not allow for that restful REM sleep, though I realize you don't prefer that route anyway. :) Before sleeping through the night consistently, we stuck to a 3 hour schedule, so it looked something like this...
6am wake and eat
7:30-9am down for a nap
9am (wake if needed and) eat
10:30-noon down for a nap
noon (wake if needed and) eat
1:30-3pm down for a nap
3pm (wake if needed and) eat
4:30-6pm down for a nap
6pm (wake if needed and) eat
7:30-9pm down for a nap
9pm (wake if needed and) eat
10:30 feed final meal before bed and to bed for the night
feed only as demanded in the night
Once your baby is consistently sleeping through the night, signs of being able to go to a four hour schedule would be consistently needing to wake baby for feedings and not being so interested in eating when it is time. That is when it is time to stretch to a 4 hour schedule. Nap time is halfway between the start of feedings regardless of how "tired" the baby looks to be. Once baby shows signs of sleepiness, they are overtired and it becomes harder for them to fall asleep and stay asleep, so it becomes a tough cycle to break. Typically when you lay the baby down when settled into the schedule, he will be alert and content, but then when laid down, he will also drift to sleep quickly because his body is used to the routine. My first son (now 3.5) took to the schedule really easily. My second son (2 years now) took a little longer to get adjusted to the routine as he was not that great of a sleeper naturally, but he turned into an EXCELLENT sleeper, though a light sleeper still. Within a couple weeks at least, he should be used to the schedule and follow it pretty much himself. Somebody mentioned to read child development books because it is normal for a 4 month old to wake 2-3 times a night. I have a degree in early childhood, a degree in psychology, have worked with kids for years, have 2 of my own, have read many baby books and completely disagree. I guess it depends on what books you read. It's not uncommon, but it is not normal and healthy either...a 4 month old is surely capable of sleeping through the night. A routine helps to encourage it. You are doing well in trying to encourage healthy sleep! :) Feel free to write back with any other questions about it or anything. :)