Why was Harry left on the Dursleys' step with a note? Why didn't Dumbledore explain in person? Considering Dumbledore, years later, was perfectly willing to pay a personal visit to the Dursleys to explain something serious to them, why did he not do the same on the night of Harry's parents' murder? Why would he leave a baby on the doorstep all night, unprotected, with no guarantee of what would happen to him? I mean, Dumbledore was right there at their house - any logical reason why he couldn't just ring the doorbell?