The 4 S's are in Tracey's new book. The 4 S's are used when putting your LO down to sleep: 1)Set the Stage: darken room, use same soothing words, turn on fan, etc. 2)Swaddle, 3)Sit (not rock!): cuddle, wind down baby w/o rocking or swaying, 4) Shh/Patt (if baby needs help settling). Not sure if 4S's are listed anywhere else on message boards, but that has worked well for us and my 6 week old goes down for bed very well b/c of it.