Jake opens the novel with a brief but pithy description of Robert Cohn’s past and present. We get to know his character before we even meet him. A brief history of Cohn’s life: Cohn goes to Princeton and becomes a boxing champ. He graduates, "is married" by the first girl that comes along, is left by said girl, and becomes a kind of literary type. He picks up a new lady friend, Frances, moves to Paris, and attempts to be a writer.At dinner, Cohn kicks Jake under the table for mentioning another girl, revealing above all else that Frances has him totally whipped.Cohn goes to the US, has a book published, and turns arrogant.He reads W.H. Hudson and hates Paris.Cohn has coffee with Jake and they argue again about South America. Cohn asks Jake about Brett. He takes offence at Jake’s declaration that Brett doesn’t love Mike, her fiancé. Cohn has the hots for Brett, and gets in a tizzy when he thinks Jake has insulted her (even though he’s just telling the truth).The next day, Cohn runs into Jake and Harvey. He irritates Harvey, who then leaves. Cohn has coffee with Jake and tells Jake that he’s struggling to write.Frances shows up at the café and berates him.Cohn goes out of the country for a few weeks.Cohn sends Jake word that he’s in Spain and agrees to meet Jake, Bill, Mike, and Brett in Bayonne to travel together to Pamplona for the running of the bulls.Cohn meets Bill and Jake at the train station.Jake, Bill, and Cohn drive to Bayonne. Cohn acts really awkward because he’s not sure if Bill and Jake know about his affair with Brett.During dinner, Cohn and Bill go to the train station to see if Mike and Brett have arrived. They haven’t. Cohn announces he’s going to stay in Bayonne and wait for them to arrive.Jake, Brett, and Cohn check out the bulls while Mike and Bill hang out at a café.Upon their return, Mike calls Cohn a cow. Cohn is offended and sulks off.The following day, Cohn parties hard! Jake finds him passed out in someone’s shop. He parties all night with the gang and watches day one of the bulls running at the crack of dawn.Cohn is a little freaked out about the gore at the first bull-fight.A few days into the fiesta, Mike attacks him again. Jake grabs him and they walk off before things get worse.Brett and Jake are chatting and she tells Cohn to go away so they can talk alone. Cohn grudgingly leaves but loiters outside the door of the café.Cohn shows up at a café where Jake, Mike, Bill and Edna are sitting and demands to know where Brett is. Jake won’t tell him. In a fit of rage, Cohn hits Jake and Mike.Cohn feels guilty, asks for forgiveness, and announces he’s leaving in the morning. In the meantime, he finds Brett in bed with Romero and he beats up Romero.Mortified, Cohn leaves in shame.