Michelle Trachtenberg was one of those cases of "gone too soon" ... and we're marking what would have been her 40th birthday by sharing a gallery of photos from throughout her career.

The performer started off her professional journey when she was just a kid, and her star really shone during her multi-season run on "Buffy the Vampire Slayer." Gallery Launch Gallery Getty

In February, she was found dead in her New York City apartment , and several of her past costars paid tribute to the late actress.

For a refresher on her work life, we've included a video showing her growing from a child actress into a full-fledged star.

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