Bookmaker hires bookies to earn from racing, another step up in train hideout income. It needs Pub Games.
Bookmaker is entry 11 of 13 in the Swindler branch, one of the three branches (Ringleader, Insider and Swindler) on the Rooks' 39-upgrade board. It is bought with money and materials, not skill points: £12,000, 100 Leather, 50 Silk. Before Bookmaker unlocks you need Pub Games.