巨大的成功背后，一场围困Def Leppard 10年的恶梦开始酝酿了。先是在《纵火狂》世界巡演中乐队的创始人----彼得.威而司由于酗酒被队友开除，以另一位吉他手菲尔.科伦替代。1984年除夕，鼓手艾伦在一次车祸中险些丧命，左臂被切除。这下子人们以为Def Leppard要偃旗息鼓了。然而，艾伦在乐队成员的支持和鼓励之下，凭着顽强的意志和天生的乐观主义精神，利用腿和手的合拍性苦练不缀。 　　4年后，全世界膛目结舌：1987年耗资500万美元制作的第四张专辑《歇斯底里》(Hysteria)卖出近1500万张。这一辉煌成绩，成为主唱乔.艾略特向人们炫耀的资本：“嘿嘿，看看，接连两张唱片都卖出1000万张，这是个唱片业的奇迹。没有谁能做到，“甲壳虫”，“滚石”，“THE WHO”做不到，迈克尔·杰克逊和乔治·迈克也做不到，当然，如果谁能做到，那就是我们！”。 　　的确，Def Leppard是支亲和力很强的商业性乐队，这一点点只要简单的从他们那优美的旋律和豪华的和声上就可以发现。有何况他们不象“枪炮与玫瑰”那样爱惹事生非，多义性他们的音乐不仅能吸引年轻人，也同样能打动他们的父母。这样的结果使得携儿带女的情况每每出现在演唱会上，而能形成这种局面的，世上恐怕只有他们和“Bon Jovi”了。可是，有时乐队的音乐特性有显得难以琢磨，他们既不象其他金属乐队那样有着明显的炫耀性技巧，有不会刻意追求流行乐那种让人崇拜的效果。他们总是坚持自己略带怪异的风格----创造性采集的流行金属。很难从他们或高昂激越或粗犷豪放或细腻柔情中找出端倪。他们一会儿拨弄出和谐的音调和嘠吱的吉他的来复，以及大量使用键盘（如《纵火狂》），但一会儿又在《歇斯底里》里使用片断式的SOLO和精巧的编排来浇铸美妙的和声。从这个意义上讲Def Leppard成为乐迷和批评家的宠儿。但更重要的是Def Leppard是一支尽管充满创伤和悲剧色彩，却又永不停止的传奇乐队。《滚石》曾说：“这个乐队最大的性质是意志力强于才能”。 　　Where Pyromania had set the standard for polished, catchy pop-metal, Hysteria only upped the ante. Pyromania's slick, layered Mutt Lange production turned into a painstaking obsession with dense sonic detail on Hysteria, with the result that some critics dismissed the record as a stiff, mechanized pop sell-out (perhaps due in part to Rick Allen's new, partially electronic drum kit). But Def Leppard's music had always employed big, anthemic hooks, and few of the pop-metal bands who had hit the charts in the wake of Pyromania could compete with Leppard's sense of craft; certainly none had the pop songwriting savvy to produce seven chart singles from the same album, as the stunningly consistent Hysteria did. Joe Elliott's lyrics owe an obvious debt to his obsession with T. Rex, particularly on the playfully silly anthem "Pour Some Sugar on Me," and the British glam rock tribute "Rocket," while power ballads like "Love Bites" and the title track lack the histrionics or gooey sentimentality of many similar offerings. The strong pop hooks and "perfect"-sounding production of Hysteria may not appeal to die-hard heavy metal fans, but it isn't heavy metal — it's pop-metal, and arguably the best pop-metal ever recorded. Its blockbuster success helped pave the way for a whole new second wave of hair metal bands, while proving that the late-'80s musical climate could also be very friendly to veteran hard rock acts, a lead many would follow in the next few years.