Two small (6 5/8 x 6 1/2), minimal volumes--in a series designated ""MY WORLD"" --which have little but recognition-value for young children. Happy Birthday To Me begins with a (stagy) toddler-like ""Look what a big boy I am!"" and proceeds to depict an average sort of small-fry birthday party--with the birthday boy involved in making the cake, blowing up the balloons, setting the table, etc. The party itself is a multi-ethnic gathering; the kids duly play Pin the Tail on the Donkey and hunt for peanuts; the presents are a likely assortment; Dad takes a picture of the cake--the Rockwells, in short, have thought of everything except how to bring this ritual occasion to life. I Play in My Room is, if anything, more moribund (and quite--inescapably--suburban middle class). A little girl introduces her stuffed animals, then rides her toy bus around the room to ""my barn,"" ""my bookcase,"" ""the horse my grandfather made,"" ""the bed where my rag doll sleeps,"" ""the blocks I build with,"" etc. At each stop, some little something takes place (at the doll's bed, ""Shhh! Don't wake her""; at the blocks, ""What do you think I am building now?""); but one might object, still, that the book is little more than an inventory of possessions. There is a teeny incident near the close--hearing her mother's footsteps, the little girl hides under the bed; but the sign-off returns to the main motif: ""My room is full of things that are fun for me!"" Neither book extends the subject in any imaginative or emotionally-tinged way, and the second limits, or reduces it, more than need be.