We went to Cambridge a few weeks ago (my iPhone speaker was buzzing and I wanted to get it checked out; Apple replaced the whole phone and sent me on my way!), and we wandered in to Heffers. We were walking over to check out the knitting books, followed by YA fantasy (me) and the model train books (John). I spotted an author doing a signing, and recognised one of the books as one that we have at home (Persian Fire, the blue book in the bottom right corner of the picture below).
"Hey, husband, don't you have that book?"
"Wow! It's Tom Holland!"
"You should buy his books and get them signed!"
The line was 1 person long (not really a line at all), so we stood and chatted to Mr. Holland for about 5 minutes while he signed 2 books for John. Then someone appeared in line behind us and we stopped hogging the author.
It turns out that the copy of Persian Fire we have at home is actually John's second copy; he gave the first one away to someone who he thought would enjoy it. When we mentioned that to Mr. Holland, he looked like he wanted to give John a medal.
We now have 2 new Tom Holland books, both signed. Sweet! I haven't read any of them yet but John thinks they're great.