A new firm launches as their first book a racy, readable picture of rulers of Europe who have come to power by using one method or another endeared to moving picture fans by American gangsters. Some almost backneyed figures -- but with a new siant; some less familiar ones, such as Horthy and Goemboes of Hungary, Corol of Roumania, the Karageorgeovitches of Jugo-Slavia, Zog of Albania, a revealing side-light on Europe's seething caldron. Slangy, journalese in style -- but readable. And there is fresh material included.