been fully explained. Spider-Man successor artist John Romita Sr., in a 2010 deposition, recalled that Lee and Ditko "ended up not being able to work together because they disagreed on almost everything, cultural, social, historically, everything, they disagreed on characters..." In successor penciler Romita Sr.'s first issue, No. 39 (Aug. 1966), nemesis the Green Goblin discovers Spider-Man's secret identity and reveals his own to the captive hero. Romita's Spider-Man – more polished and heroic-looking than Ditko's – became the model for two decades. The Lee-Romita era saw the introduction of such characters as Daily Bugle managing editor Robbie Robertson in No. 52 (Sept. 1967) and NYPD Captain George Stacy, father of Parker's girlfriend Gwen Stacy, in No. 56 (Jan. 1968). The most important supporting character to be introduced during the Romita era was Mary Jane Watson, who made her first full appearance in No. 42 (Nov. 1966), although she first appeared in No. 25 (June 1965) with her face obscured and had been mentioned since No. 15 (Aug. 1964). Peter David wrote in 2010 that Romita "made the definitive statement of his arrival by pulling Mary Jane out from behind the oversized potted plant [that blocked the reader's view of her face in issue #25] and placing her on panel in what would instantly become an iconic moment." Romita has stated that in designing Mary Jane, he "used Ann-Margret from the movie Bye Bye Birdie as a guide, using her coloring, the shape of her face, her red hair and her form-fitting short skirts." Lee and Romita toned down the prevalent sense of antagonism in Parker's world by improving Parker's relationship with the supporting characters and having stories focused as much on the social and college lives of the characters as they did on Spider-Man's adventures. The stories became more topical, addressing issues such as civil rights, racism, prisoners' rights, the Vietnam War, and political elections. Issue No. 50 (June 1967) introduced the highly enduring criminal mastermind the Kingpin, who would become a major force as well in the superhero series Daredevil. Other notable first appearances in the Lee-Romita era include the Rhino in No. 41 (Oct. 1966), the Shocker in No. 46 (Mar. 1967), the Prowler in No. 78 (Nov. 1969), and the Kingpin's son, Richard Fisk, in No. 83 (Apr. 1970). 1970s Several spin-off series debuted in the 1970s: Marvel Team-Up in 1972, and The Spectacular Spider-Man in