"Fooling Yourself" is the second single released from Styx's The Grand Illusion album. On the Billboard Hot 100 pop chart in the U.S., the single peaked at number 29. It also hit #20 on the Canada RPM Top Singles chart the week of May 6th 1978.

The song was written by guitarist Tommy Shaw. It was originally based on Shaw's initial perception of Styx keyboardist Dennis DeYoung — an "angry young man" who viewed the group's successes with a wary eye and grew angry or depressed with every setback. It was only in later years that Shaw began to see himself in the lyrics, and the song took on a more personal meaning to him.

The composition features a number of time signature changes. The intro and outro are performed in 6/8 time, led by Shaw's acoustic guitar tracks and Dennis DeYoung's synthesizer melodies. The vocal sections of the song are in 4/4. The instrumental features a synthesizer solo in 7/4 time, before returning to 4/4 for the final chorus. After a brief intro recap, there is a brief break with two measures of 5/8 time, and then a return to the 6/8 meter, with another synthesizer solo, before fading out.

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