If Alan Leo made astrology about your character, Dane Rudhyar made it about your becoming, and he did it as an artist, not a fortune-teller.
Rudhyar was an incredible polymath: a composer and painter first, who got deep into philosophy and astrology. And in 1936 he wrote The Astrology of Personality, which rewired the whole field by plugging it into Carl Jung's psychology.
Here's his big idea, and it's a good one even if you don't care about astrology at all: your birth chart is a seed pattern. Not a prediction of events, a picture of your full potential. The complete version of you that's trying to grow. And your life is the slow, messy process of becoming that.
Because he was a musician, he saw the chart the way you'd see a piece of music: a whole composition with a central theme you keep returning to and developing over a lifetime. Not 'this will happen to you,' but 'this is the song you're here to play, now go play it well.'
That reframe is everywhere now. Every modern astrologer talking about your chart as a tool for self-development, for becoming who you really are, that's Rudhyar's DNA. He turned the night sky from a crystal ball into a mirror for growth.