I really don't think he's dead.
This is the opening line of the novel. Marcus says this to Packy, Flossie, and Tipper. Jack says something at the end of the novel, when lies dying and tells Marcus, "I really don't think I'm dead." The line is not to be taken literally. It means that Jack lives because he has a hold on the American imagination. The legend of Legs Diamond survives the death of the man. Marcus uses this statement as a touchstone for seeking out all of the many ways Jack Diamond lived, both before and after his death. Even during Jack's lifetime, it was obvious that the myth of Jack "Legs" Diamond had a life of its own, a myth that was built up and cut down by the press and by word of mouth. After Jack's death, the stage shows of Kiki and Alice kept his reputation fresh. And four and a half decades later, with the creation of Legs, Jack lives in the pages of this novel.
I had no pressing business in New York, but I made it a point to go, and I presume it was for the same reason I'd helped old Jesse frame a new identity for himself and then got him a job in Boston—because I was now addicted to entering the world of Jack Diamond as fully as possible.
Marcus states this right before he decides to go visit Kiki in Manhattan. Marcus, Kiki, and Alice all go through periods during which they consider ending their relationships with Jack. Whether they are fed up with Jack's unsavory mobster tactics, his penchant for sleeping around, or the fact that he is always leaving them alone with one of his henchmen, each character occasionally decides that the relationship is not worth it. Alice and Kiki do actually leave, and at one point Marcus considers himself no longer in Jack's employ. But they all come back. In a sense, they are all "addicted" to Jack, as Marcus says in this passage. Marcus is looking for something more interesting than the life afforded a small town lawyer; Kiki realizes that being Jack's broad will make her more famous and sexy than her dancing ability ever could; Alice is challenged by her Catholic faith and her wedding vows to keep wandering Jack by her side. But, more basically, they are all attracted by their association with Jack's fast- paced, bad boy, dangerous lifestyle.
When she saw [the piece of plaster] she laughed a soft little laugh and told me the squiggle marks were hers; that she'd made them the first weekend she and Jack were married; that they stayed in an Atlantic City hotel and hardly went out except to eat and that they'd made it together twenty-five times. After number five, she said, she knew they'd only just started and she kept the score on the wall next to the bed. And when they checked out, Jack got the tire iron from the car and hacked out the plaster with all the squiggles on it.
Alice says this after Jack has died. The police returned the piece of plaster, along with some of the other possessions of Jack's that they had confiscated. For the most part, Kiki takes up the sexual part of Jack's life. But this quotation shows that at one time, Alice and Jack's relationship was very sexual. This side of Alice is not immediately evident in most of the novel.
[T]wenty minutes and two old-fashioneds later we were all in the elevator descending to the Rain-Bo room, my own pot of gold tucked away in a breast pocket.
Marcus says this on his way to dinner with Jack, Alice, and Kiki. Jack has just paid his legal fee to Marcus: ten thousand dollars in five hundred dollar bills. Marcus keeps Jack on as a client mainly because his association with Jack excites him. Firing machine guns, smuggling stolen money, and seducing anonymous women are not the kinds of activities Marcus enjoys with any of his other clients. Marcus also likes his association with Jack because it provides him with plenty of money. When Fogarty cannot pay Marcus's legal fee, Marcus drops him immediately, which proves that rubbing shoulders with the notorious is not quite enough for Marcus. It does thrill Marcus to rub shoulders with Jack, however, whatever the allure of the money. When Marcus refers to Jack's payment as "his own pot of gold," it suggests that Marcus sees the payment he collects as evidence that he is one of Jack's collaborators. Marcus enjoys the idea that he is getting rich as a result of Jack's gangsterism.
I had come to see Jack as not merely the dude of all gangsters, the most active brain in the New York underworld, but as one of the truly new American Irishmen of his day; Horatio Alger out of Finn McCool and Jesse James, shaping the dream that you could grow up in America and shoot your way to glory and riches.
Marcus states this near the beginning of the novel, as he introduces the legend of Jack Diamond. Finn McCool is a legendary hero of Old Ireland, a giant of mythological proportions. Jesse James is a famous outlaw and an American legend. Horatio Alger is a novelist who wrote tales of poor boys succeeding in America by dint of hard work and luck. Here the narrator suggests that Jack is like the hero of an Alger novel and also an amalgam of McCool and James—a hero who succeeds not through hard work and luck, but through violence.