The 32-bar form, also known as the AABA song form, American popular song form and the ballad form, is a song structure commonly found in Tin Pan Alley songs and other American popular music, especially in the first half of the 20th century. As its alternative name AABA implies, this song form consists of four sections: an eight-bar A section; a second eight-bar A section (which may have slight changes from the first A section); an eight-bar B section, often with contrasting harmony or "feel"; and a final eight-bar A section. The core melody line is generally retained in each A section, although variations may be added, particularly for the last A section. Examples of 32-bar AABA form songs include "Over the Rainbow", "I Got Rhythm", "What'll I Do", "Make You Feel My Love", "The Man I Love",, "Dream River," "Primrose Lane," "Let's Get Away From It All," and "Blue Skies". Many show tunes that have become jazz standards are 32-bar song forms. Basic song form At its core, the basic AABA 32-bar song form consists of four sections, each section being 8 bars in length, totaling 32 bars. Each of these 8-bar sections is assigned a letter name ("A" or "B"), based on its melodic and harmonic content. The A sections all share the same melody (possibly with slight variations), and the recurring title lyric typically falls on either the first or last line of each A section. The "B" section musically and lyrically contrasts the A sections, and may or may not contain the title lyric. The "B" section may use a different harmony that contrasts with the harmony of the A sections. For example in the song "I've Got Rhythm", the A sections are in the key of B, but the B section involves a circle of fifths series of dominant seventh chords going from D7, G7, C7, to F7. Song form terminology is not standardized, and the B section is also referred to as the "middle eight", "bridge", or "primary bridge". The song form of "What'll I Do" by Irving Berlin is as follows: {| class="wikitable" !Name !Lyric from "What'll I Do" by Irving Berlin |- | align="center" | A1 |What'll I do when you are far away and I am blue? What'll I do? |- | align="center" | A2 |What'll I do when I am won'dring who is kissing you? What'll I do? |- |