The squabble over a piece of land next to the site of the John F. Kennedy Memorial Library is a curious--but very valuable--reminder of how much the City needs to control development around the Library.

The disputed building is a four-story apartment which Harvard had an option to buy. The University decided it wanted the building, and showed up at the Middlesex County Registry with cash; the owners failed to appear. They will have their chance to tell why in court next month and to argue that Harvard's option shouldn't be enforced. Meanwhile, the reason for their reluctance to sell is obvious: the land's proximity to the Library has made the option price ridiculously low.

The lesson is plain. Competition for land around the Library is going to be fierce. Moreover, the annual influx of tourists will undoubtedly stimulate development. New construction could bring a series of unsightly, uncoordinated, and unwanted buildings. Accommodating this large number of visitors is necessary; abandoning the place to them is not. Clearly, the City needs some means of regulating the real estate pressures now being exerted on the Square.

Cambridge officials have talked informally about urban renewal in the Harvard-Brattle area. But the project doesn't seem to have moved very far. Using renewal the City could control demands put on real estate: the men with the biggest pocket books would not be able to decide unilaterally what should be built in the Square and how it should look.

Unfortunately, the longer the urban renewal concept remains domant, the more difficult it will be to implement it in the future. Real estate dealers and potential investors won't wait until the City is ready to introduce the idea. They will try to purchase the most desirable spots in the Square and, in some cases, begin to plan new buildings. The more of them there are, the more pressure will be put on the City Council to either reject urban renewal or reduce its scope. And even if a plan is eventually passed, it could be distorted when it is put into practice.

Moreover, there are dangers in the renewal concept itself -- possibilities that too much control would damage the eventual character of the Square almost as much as uninhibited private development. A plan should be published early enough to allow for discussion and dissent on details, as well as the central concept. If delay is too long, those who support renewal in principle but disagree with parts of a proposal may be forced to abandon their criticisms, or to go to the other extreme by opposing the plan in its entirety. Neither prospect is very pleasing.

It is easy to wait now. There is no construction on the Library site of the Bennett St. M.B.T.A. yards, and there probably won't be for the next two years. But when the first bulldozers do arrive, it may already be too late to come up with anything more than a crippled proposal.