5 pages | PDF | 1.3 MB"Shadow of a Doubt" by Tom Petty and The Heartbreakers is an upbeat rock song composed in A major and F♯ minor. The song is made up of 67 measures, and is filled with heartfelt lyrics, upbeat rhythm guitar, and a driving beat. The chorus is catchy and memorable, and the overall production and instrumentation are top-notch. The song explores themes of doubt, insecurity and resilience, and speaks to Petty's wide-ranging musical skill. It's sure to be a fan favorite and classic Petty track.