Re-ac-tor is the eleventh studio album by Canadian musician Neil Young, and his fourth with Crazy Horse, released in 1981. The album married the electric guitar crunch of the late 1970s Crazy Horse sound with early 1980s new wave rhythms. The simplistic, overdriven sound of the songs can be seen as a continuation of the punk-influenced numbers of Rust Never Sleeps such as "Sedan Delivery."
Critical reception to the album was generally poor except for the accolades accorded to the album closer "Shots." The album marked the first use by Young of the Synclavier which would be featured heavily on several of his later albums: Trans (1982) and Landing on Water (1986).
The album features the Serenity Prayer on its back cover ("'Deus dona mihi serenitatem accipere res quae non possum mutare fortitudinem mutare res quae possum atque sapientiam differentiam cognoscere'" – "God grant me the serenity to accept the things I cannot change, the courage to change the things I can, and the wisdom to know the difference").