The Merchant Murders Mysterious Book Report No. 503 by John Dwaine McKenna As The Merchant Murders, (Severn, $29.99, 240 pages, ISBN 978-0-7278-5092-8), by Michael Jecks opens, it’s the middle of the 16th century in not-so-jolly old England, where we continue following the adventures of a daring, raffish and rascally young rogue named Jack Blackjack . . . who’s an assassin in the employ of Lady Elizabeth—Queen Mary’s sister—at a