Van Rijn And Poirot

the canny trader van Rijn survives, prospers and profits only if he continues to understand ever new examples of alien biology and psychology and Anderson can imagine these as genuinely alien by reasoning from the basic premises of different stellar and planetary environments. Van Rijn’s deductive processes resemble Hercules Poirot’s. He works hard at thinking out new situations even while lounging and drinking beer but is physically powerful and skilled enough to handle himself in a fight with an alien warrior if necessary.
-copied from here.

Both are intelligent. One detects. The other trades.

Van Rijn speaks Anglic with malapropisms. Poirot speaks English with a trace of French.

Both are Catholic, like Fr. Brown. Van Rijn invokes St Dismas. Poirot at the end puts himself outside the Church's way to salvation by murdering a murderer. He cannot confess to a priest and must ask God directly for forgiveness.

Poirot's Last Case is on TV.