Widely considered the best metal record of all time, Metallica's "Master of Puppets" is the gold standard when it comes to heavy music. Lyrics feature violence, fear, and social outrage, combined with pounding percussion,powerful palm-muted riffs, and wild solos. The lyrics will concern many a parent, but I would like to point out that the ideas featured are typical of testosterone-fused young men, if not a bit wise for the age group, as the album assails social injustices and explores painful, creative topics. This is music that actually says something, as compared to many modern popular artists, who focus on sex, butts, dances, and other shallow topics that really mean nothing at all. 14+ boys will love this music. I've been listening since age 13 and Metallica is still my favorite bands. As parents i would advise listening to the music yourself, giving it a chance, and as always, keep in mind that some kids are more mature than others. Some at 14 may be mature enough to handle it and some may not.