Irish biographer MacNamara's first novel: an elaborate Celtic sendup of literary pretensions filled with what's described as ""utter and hopefully pleasant nonsense."" The title, a mischievous pun on the revered The Book of Invasions (""a compilation of records from early Irish mss.""), sets the tone for this long Irish shaggy-dog story -- the story of Mountmellick and MacGilla, two characters who escape from limbo, which, ""by Vatican decree or omission, [had become] tenantless,"" subsequently to be occupied by ""characters from unpublished novels, filmscripts, narrative poems and other sources of synthetic personality."" The escaped pair take over a writer's mind as a first step to the gaining of immortality previously denied them. Unlike many of their colleagues, they have no wish to ascend to Parnassus, preferring instead to make their names in the present. Meanwhile, the writer's mind provides them with the energy to ""encorpify,"" but once that's done they're ready to act on their own. Which they do as they recruit Loreto Armagente, whose parents appeared in an unfinished short story by F. Scott Fitzgerald; the Celtic poet Liadin, as imagined by George Moore in an unfinished historical novel; and the eight-foot-tall feminist, Eevell of Craglee, Queen of the Munster Fairies, from an unfinished poem by Brendan Behan. With all ""the Irish acceptance of the labyrinthine nature of reality,"" they brawl in pubs, give their odd versions of Irish history, move to London, start their own publishing house, and imprison the author in their house in Hampstead. But, as a writer, he has the last word: he smuggles out a story about them that will certainly get published. A gentle skewering of a lot of sacred cows with lots to amuse, though the good times often get lost in the dense mists of Irish history.