Metallica is releasing expanded reissues of Kill 'Em All and Ride the Lightning, their initial two multi-platinum albums.

Both reissues, due on April 15, have been remastered and will be available in CD, vinyl and deluxe box set editions. The boxes include original source material from Metallica's personal collection, much of it never before released, along with a book featuring rare content.

The band earlier asked fans for help in compiling rare content for these boxes. They are now promising similar reissue treatment for subsequent albums, as well. "We’re excited to continue working our way through the catalog," Metallica said via their website. "This is just the beginning."

The deluxe, numbered box set for 1983's Kill 'Em All features four vinyl records, five CDs, one DVD, the special book and a patch. Vinyl highlights include a live show from Paris in 1984, over two LPs, and the Jump into the Fire picture disc. The CD package includes an interview disc, two unreleased shows, and a disc of rough mixes and bootleg tracks. The DVD was recorded live in Chicago in 1983.

The box for 1984's Ride the Lightning includes four vinyl records, six CDs, one DVD, the book, a mini-book of lyrics handwritten by James Hetfield and a set of three posters. The vinyl set includes a 1985 show in L.A., and the Creeping Death picture disc. The CD set features a trio of concert recordings, while the DVD includes a largely unavailable 1985 set from the Metal Hammer Festival in Germany, plus additional performances.

Click here for a complete look at the track listings. These reissues will be available via Metallica's web store, and on local shelves in time for Record Store Day.

Kill 'Em All, Metallica's debut, sold three million copies in the U.S. alone on the strength of thrash-metal classics like "Whiplash" and "Jump in the Fire." They followed that up with the six-times platinum Ride the Lightning, a more musically diverse effort highlighted by "For Whom the Bell Tolls" and "Fade to Black," among others.

Metallica Albums, Ranked Worst to Best