Letters From Home
<spoiler> The clue above the entry box means to look at the name of the hotel: datoname hotel = day to name.
So take the day of the month given in the post marks, and then take the country name on the stamps. Sometimes you'll have to figure out the country.
Apply the number to the name like this: Nov 7 + United States = United States = S
You get "St Paul's Cathedral".
The hint from the london projection is "Photographer"
Answer: HERBERT MASON . He took the photograph of the 1940 bombing of St Paul's Cathedral in London. </spoiler>
<spoiler> Working top to bottom, left to right gives the following:
Nov 7 - United States
Apr 9 - Great Britain
May 1 - Poland
Dec 2 - Japan
Jan 2 - Bulgaria
Jul 8 - Switzerland
Mar 2 - Estonia
Feb 1 - China
Jun 7 - Romania
Oct 2 - Italy
Aug 1 - Hong Kong
Sep 4 - Argentina
Nov 10 - New Zealand
Jun 3 - Norway
Apr 6 - Canada
May 7 - Australia
</spoiler>
Next book: Mural