Book excerpt: Cassidy presents a history of the Irish influence on American slang in a colourful romp through the slums, the gangs of New York and the elaborate scams of grifters and con men, their secret language owing much to the Irish Gaelic imported with many thousands of immigrants. With chapters on How the Irish Invented Poker and How the Irish Invented Jazz, Cassidy stakes a claim for the Irishness of American English. Includes a preface by Peter Quinn and an Irish - American Vernacular Dictionary.