1st Infantry is the debut solo studio album by American hip hop producer and recording artist The Alchemist. It was released on September 21, 2004, through Koch Records. Recording sessions took place at The Lab, Baseclef Studios and Infamous Studios in New York City, at Soundproof and MGS Sound Lab in Los Angeles, and at D-Block Studios in Yonkers. Production was handled entirely by the Alchemist, who also served as executive producer together with his brother Neil Maman, with Prodigy serving as co-executive producer. It features guest appearances from The Lox, Mobb Deep, Big Noyd, Big Twins, B-Real, Chinky, Devin the Dude, Dilated Peoples, Illa Ghee, Lloyd Banks, M.O.P., Nas, Nina Sky, P$C, Stat Quo and The Game.

Alan Daniel Maman, professionally known as the Alchemist, is an American hip hop producer, DJ, and rapper. He began his music career in 1991 in the hip hop duo the Whooliganz under the moniker Mudfoot, along with now-actor Scott Caan. He has produced music since the 1990s.