Star Wars has them. So do the Star Trek and Red Dwarf series. Which work of Scifi/fantasy, written or filmed, was the first to depict a person as a hologram?
The earliest I can think of (though there are likely others) is Foundation, published in 1951. Hari Selden appears several times as a holographic recording, warning the populace of impending crises. However, I'm pretty sure the word hologram is actually used in the book, so the thing to figure out might be who coined the word and when.
Obviously, the benchmark to beat is 1974 when Star Trek: The Animated Series episode "The Practical Joker", introduced the holodeck.
The Carpathian Castle (1893 novel by Jules Verne) the plot revolves around prima donna La Stilla, represented at the times of the events as a projected image.
I'm not sure if that counts (it was a projection but not technically speaking a hologram) but will post in case you meant to include any projections and not just literally holograms.
If that doesn't count, Lem's "Return From The Stars" (1961) has "holographic 3-D photos, as well as holographic theater plays" according to TVTropes.
What about the Wizard of Oz (1939 for the movie, not sure if this was seen in the books)? Maybe not a hologram in the strictest definition, but the technique is pretty similar.