The album's first single, "Who Says" challenges conventional standards of what one can accomplish or undertake - despite society's constraints. Battle Studies also showcases universal themes on "Heartbreak Warfare," "Assassin," and "War of My Life," while flexing guitar chops on "Rock Song," and a reinterpretation of "Crossroads." The famously collaborative guitar player also invited one of music's brightest new talents, Taylor Swift, to appear on "Half of My Heart.“ "I approach music like a director doing a period piece," says Mayer. "Where Continuum was R&B and Soul, Battle Studies was written with the timelessness of Tom Petty, Fleetwood Mac and Neil Young in mind. The melodies and message are concise and from-the-gut with the efficiency of simplicity."