Who produced Metallica's 1986 album 'Master of Puppets'?

Flemming Rasmussen produced Metallica's 1986 album Master of Puppets, working with the band at Sweet Silence Studios in Copenhagen, Denmark.

Rasmussen was a Danish sound engineer and producer who had already worked with Metallica on Ride the Lightning, their 1984 breakthrough. The successful partnership continued on Master of Puppets and later ...And Justice for All, making him an important figure in the band's classic 1980s sound.

Master of Puppets was recorded from October through December 1985 and released on March 3, 1986. The album became one of thrash metal's defining records, combining fast, intricate arrangements with darker themes about addiction, war, manipulation, and mental confinement.

The answer is sometimes confused with Bob Rock, who produced Metallica's self-titled 1991 album and later records, or Rick Rubin, who produced Death Magnetic. Rasmussen's production credits also include albums by Rainbow, Morbid Angel, Blind Guardian, and Ensiferum.