I came to Ross Macdonald pretty late, after I’d already burned through a lot of Chandler and Hammett. Honestly, for a starter, I'd argue against picking 'The Moving Target', which was his first Lew Archer. It’s good, but it reads more like he’s trying on Chandler’s suit. The real jump in quality, for me, was 'The Drowning Pool'. It’s where his own voice clicks into place—less about the wisecracks, more about the psychology simmering under the California sunshine.
From there, I think you should go straight to 'The Galton Case'. That’s the novel where he fully perfected his signature move: the family secret buried in the past. The plot revolves around a missing heir, but it spirals backward through time, peeling away layers of identity and buried trauma. It’s less a whodunit and more a ‘why-dunit’, and Archer becomes more of a therapist digging through the ruins of a family. That book set the template for everything brilliant he did afterward.
If you like that, then 'The Chill' and 'The Far Side of the Dollar' are the logical next steps. They refine that formula to a razor’s edge. But starting with 'The Drowning Pool' into 'The Galton Case' gives you the perfect arc of seeing an author find and then master his great theme.