How possible is it to design a first-rate new church in the middle of the twentieth century ? Our grandchildren, perhaps, will be able to answerthis question better than we can, because what is being built now will, if it survives at all. be much easier to evaluate after it has been lived with and used for a couple of generations. Meanwhile one can at least draw up a balance sheet of our contemporary advantages and disabilities. On the positive side, the apparatus of rationality, simplicity and appeal to first principles which the modern architectural movement wrought for itself should, anyway notionally. give its present-day followers a good start – or at the very least it should preserve them from the worser kinds of pretentiousness and vacuity. A generation reared on le Corbusier's dictum that ‘the plan is the generator’ ought to be able to devise liturgical spaces that are light, plain and sensible if they are nothing more. Further, the independence from ‘historic styles’ which the modern movement asserted should make our architectural idiom more readily responsive to changes in liturgical practice and indeed to all the new kinds of religious sensibility and orientation which, long latent, seem at last to have found expression in Pope John and the Council. If, as seems tremulously possible, the Church does in fact decide to enter the twentieth century, understand it and lead it, there is available at least the makings of an architectural vocabulary to suit the purpose.