Colm Meaney appears as the nameless crewman (escorting an Antican delegate), who also appeared at the ops position in Encounter at Farpoint (1987). This character would later become Transporter Chief O'Brien in season 2 and beyond.
The first episode to reveal Data's persona of Sherlock Holmes.
One item of tech introduced in this episode which never returned was the surgical cap and eyepiece worn by Doctor Crusher.
Marc Alaimo went uncredited for the Antican, explaining "I wasn't sure how it was going to turn out, so I asked them not to put my name on it, but it turned out to be fun."
Although this is the only major appearance of either the Anticans or the Selay, they continued to be used as background extras in other episodes of The Next Generation and Star Trek: Deep Space Nine (1993).