A strange case, Flann O'Brien's. Born Brian O'Nolan, then alias-ed and realias-ed again as Myles na Goopaleen, this Irish writer crammed a lifetime with enough exceptional work and yet also enough small beer to make the idea of a ""Reader"" more than merely a handy introduction to a shadowed writer: it gives shape to a shapeless career, O'Brien's belief that ""a satisfactory novel should be a self-evident sham to which the reader could regulate at will the degree of his credulity"" produced the remarkable At Swim Two Birds in the late Thirties, in which audaciousness, literary invention, and strong humor seemed both to ease up and at the same time validate Joyce's hold on modern Irish literature. In fact, the best thing here is O'Brien's sagely pithy and not totally admiring piece on Joyce: ""He seems to have deserved equally with George Moore the sneer about the latter--he never kissed, but told."" O'Brien later abdicated his role as novelist for that of a Russell Baker-ish newspaper columnist, and then, finally, penman of TV comedy scripts--and Stephen Jones' documents in his introduction why this might have been: greatly disillusioned and hurt by the rejection of his second novel, The Third Policeman, O'Brien wasn't offered further comfort from fiction until late in his life when he returned to the form and produced two middling books. But what Jones has excerpted from The Third Policeman will come as a marvel to the uninitiated: the visionary wit, the snug-fitting language, the soaring imagination. O'Brien's limitations--too much style, too little substance--pull at this miscellany like too-tight laces, but the wonderful inner freedom peeking out here and there is irrepressible.