How do you know so much about the Old Doktor - Janusz Korczak?

Korczaks book closely related to his plans of Aliyah (returning to Israel) - Trzy wyprawy Herszka - Three Expeditions of Little Hersh, Warszawa, 1938. Hersh Goldszmit (Janusz Korczak) was named after his grandfather, Hersh.

Korczaks book closely related to his plans of Aliyah (returning to Israel) - Trzy wyprawy Herszka - Three Expeditions of Little Hersh, Warszawa, 1938. Hersh Goldszmit (Janusz Korczak) was named after his grandfather, Hersh.

Again, the same question: how do you know so much about the Old Doktor - Janusz Korczak?

"For many years I have thought that Korczak had been my granpa. His picture hanged in the home of my parents in Warsaw. It was the only picture we had at home. No picture of my grandfather Boruch from Pinsk or Gabriel from Warszawa. Boruch was murdered by Einsatzgruppen and Gabriel was murdered in gas chambers of Treblinka. Not a single photo of them left.

And again, at my parents home there were ceaseless stories about Korczak. If not for the WWII, I would have had Korczak for a granpa because he adored my father and he admired my mother. 

Most likely, in my youth, I would have been traveling for the holidays to granpa Korczak in Israel...

Janusz Korczak loved Eretz Israel and I am sure that he would end there if not WWII as Korczak was planing to make aliyah (returning to Israel). His book from 1938 - Trzy wyprawy Herszka - Three Expeditions of Little Hersh, is describing the way of little Hersh to Israel. Hersh Goldszmit (Janusz Korczak) was named after his grandfather, Hersh.