"There is a flatter market," he says, "but it is not dead at all." The market perks up in late spring or early summer because Cambridge operates on an academic year, he adds.

And while Alstein theorizes about the reasons for slow condo sales, the buildings continue springing up on both sides of Mass. Ave.

Across the street from the Bay Square development, a small frame house and a gas station have been replaced by 931 Mass. Ave., a tall, slate-grey condominium development.

"The selling has been fine," says Peter C. Kash '71, executive vice president of The Condominium Collaborative, the development's marketing company. Kash said late this fall that 29 out of 54 units had been sold.

But whatever the financial prospects for the area between Harvard and Central Squares, Harvard students and residents can't help but notice the changes.

One newcomer to the area--Shake, Rattle and Roll--seeks to capitalize on the Baby Boomers' nostalgia for 1950s memorabilia. Whether it succeeds in the market or not, perhaps the store's presence, located next to The Friendly Eating Place and down the street from the gleaming new condo complexes, is itself a metaphor for the changes that Mass. Ave. is undergoing.

Cajun food may come and go, the sushi market may bottom out--the face of Mass. Ave., though, is sure to be different.