Liza Minnelli, now 78, appeared in her first movie when she was a toddler. It was the musical romance In the Good Old Summertime, starring her mother, Judy Garland. A new documentary tackles the emotional period just after Garland’s death at 47, in 1969, when Liza was 23. Thanks to a squadron of trusty mentors, including Kay Thompson and Bob Fosse, Minnelli tackled the next decade with ferocity, adding an Oscar (Cabaret) and an Emmy (Liza With a Z) to her Tony (Flora the Red Menace), which she won as a teenager. (Her EGOT was clinched with a Grammy in 1990.) Mia Farrow and Darren Kriss are among the friends and admirers who pay homage to Minnelli in the film, while she herself reflects on the moments, both grim and glamorous, that marked her dramatic ascent in the industry. —Paulina Prosnitz