There is a moment in the early stages of the career of Kiss when Gene Simmons looks decidedly uncomfortable, and it has little to do with the four-inch heels on his studded and sparkling platform boots.
Despite his claims to be "evil incarnate", his oft-brandished tongue almost drops to the floor when a fellow guest on a 1974 instalment of The Mike Douglas Show asks what his mother thinks of his antics. For a few seconds, Simmons the unsettler is unsettled.
It's just a few seconds, mind. Self-reflection is banished like a naughty schoolboy. The tongue returns.
Yes, Kiss did get better. But there was plenty of room for improvement. Many of the band's concerts of 1974 were stodgy, ponderous affairs, highlighted (if that's the right word) by Simmons' bass playing which, if not appalling, was as unremarkable as the drumming of Peter Criss.
A year later, however, and the band was both tighter and more fluid. The rhythms were punchier, though attempts at pathos by singer Paul Stanley (the one with the star over his right eye) were slightly at odds with the 4/4 stomp so prominent in the Kiss set-list.
Comprising two DVDS, as well as a bonus CD featuring a dozen tracks from a 1977 concert in Largo, Kissology is at its best when it focuses on events off the stage.
Priceless are the 1975 scenes in Cadillac, Michigan, where council members, including the mayor, don make-up at a civic ceremony at which Kiss is given the keys to the city.
The band's response? "I hope you don't change the locks."
Later, Simmons is pictured tossing sweets to throngs of children and teenagers who follow the band along a street.
Evil incarnate? Hardly.
Reprising their epic 1985 World Slavery Tour, in 2008 the members of Iron Maiden boarded their very own Boeing 757 (piloted by singer Bruce Dickinson) and performed 23 concerts in 45 days on five continents.
The English heavy rock act may have struggled to gain mainstream radio airplay at home, but its global popularity appears undiminished some 30 years after it formed: it is mobbed in Mumbai, and likewise in Tokyo. In Los Angeles, it is worshipped by Tom Morello, of Rage Against The Machine, and Lars Ulrich, of Metallica.
Elsewhere, in Sao Paulo, Brazil, a Catholic minister delivers a sermon on the morality of Iron Maiden's lyrics.
The twist is "Father Iron Maiden", a die-hard fan, is adorned with more than 160 tattoos relating to the band.
Yet amid all the adulation, the pyrotechnics, the imposing stage artwork and the backstage banter, this two-DVD collection showcases a key point: age need not weary them.
Marshalled by bass player and key songwriter Steve Harris, augmented by the powerhouse drumming of golf fanatic Nicko McBrain and topped off by the dexterity of not one but three guitarists, Iron Maiden is caught in good form, though it's a pity Dickinson's voice can no longer reach as high as the plane he controls.
