Vice President Truman played an outsize role in world history due to the untimely demise of FDR towards the end of WWII.
Unfortunately, he was not the visionary leader that FDR is.
Truman failed to settle the China issue which led to the US abandoning CKS to be defeated by Mao. Mao was assisted by Stalin.
Truman failed to settle the Palestine issue which led to the intractable issues that now plague the entire Middle East.
These 2 books examine both failures.