Superman #23/1968

In "Der Mann vom Sirius," two alien visitors expose Superman and Batman's secret identities, spinning conflicting tales about their origins that shake the heroes' trust. As doubts take hold, the two friends clash—until Supergirl steps in to aid Batman and Batgirl joins forces with Superman to restore their alliance. Written by Cary Bates and brought to life with dynamic art by Neal Adams, this 1968 classic features cover art by Adams himself, capturing the tension with striking precision.