Spike Carlsen wrote a book about "awe walking." That was before he’d even heard the term.

His new book, “A Walk Around the Block,” is about noticing and maybe even appreciating all the amazing things right in front of you.

Of course, you may not think the wastewater system beneath the street — or the street itself — is all that amazing. But Carlsen does. And if you read the Minnesota author’s deeply researched, breezily written book (his seventh), it’s likely that his infectious curiosity will rub off on you. As he promises in his introduction, “knowing the inner workings of the world outside your front door makes life more interesting.”

We talked to the avuncular Carlsen about nerd knowledge, the multipurpose tool all squirrels have and the strangest things ever sent via U.S. mail.

Q: How would you describe your new book?

A: It’s great bathroom reading. You can pick it up and read any chapter. 

Q: You tackle a surprisingly wide range of topics: porches and potholes; sewers and squirrels. How did you make your selections?

A: The glue is a theoretical walk around a theoretical block. I knew I wanted to cover the basics, like water and electricity and sewage and telephones, but I wanted to go beyond that, to all the things you might see — parks, pigeons, street signs. 

Q: I’m the least mechanical person I know, but you managed to make me interested in electric grids. How did you do that?

A: You have to get the reader interested, but to do that you have to entertain a bit, then inform them and, perhaps in a perfect world, to engage them 

Q: You approach the more technical topics the same way you do the simpler ones. Can you describe that approach?

A: For each chapter, I tried to find a core — a person, place or event — and build around that. The goal was to winnow down the story, to get to the basics but bring a human element to it. I tried to spend about a third of the time explaining the function of, say, a power plant. But the story of things is the story of people.

Q: And you did find some interesting people, including a New Yorker who built a trash museum, an Alabama roadkill expert and a Minnesota woman who’s been dubbed the Nordic Walking Queen.

A: Yeah, you find people who are very dedicated and very knowledgeable. Thank God for nerds. I don’t mean that in a bad way. I’m a nerd.

Q: You clearly have a lot of knowledge and an endless store of fun facts. Are you ever a bore at dinner parties because you dominate the conversation?

A: Ha! No, I’m an introvert. If I have the chance to interject an amazing fact, I’ll do it. But I’m not the sort who spews out facts.

Q: You use lots of local examples and experts, but this isn’t a Minnesota-centric book, is it?

A: Minnesota is a good starting point because we get the most severe weather. So if it [the infrastructure] stands up here, it’ll stand up anywhere.

I started in my hometown of Stillwater, but I traveled to Paris for the chapters on sewers and graffiti. I went to California and New York and Alabama, Tennessee and West Virginia. 

Q: Your book has a lot of fun facts. I’m going to ask you about a few of them. What is the weirdest thing mailed through the U.S. Postal Service?

A: Aside from live rattlesnakes (which were thought to be dead), mailing children was done about three times. In every case, there was a back story — the mail carrier knew the neighborhood, it wasn’t very far. … They didn’t put stamps on a kid’s forehead. But it was serious enough that the postmaster general had to issue a statement [against the practice].

Q: You give an engaging history about what might seem to be a deadly dull substance: concrete. What is it?

A: The Romans had an early recipe for concrete. The trick was to be able to heat limestone to 1,200 degrees. They built the Pantheon — it’s a magnificent structure and it’s one of the earliest domes made of concrete. But with the decline of Rome, the formula just kind of got lost.

Q: What’s so cool about the tails of squirrels?

A: A squirrel tail is a multipurpose tool. They can use it like a balancing pole, like a tightrope walker. In the summer, they use it to dissipate heat, in the winter to gather heat. They even use it as a warning signal.

Q: What’s the most common street name in the country?

A: It’s kind of weird and kind of unexpected: It’s 2nd Street. So often, there is a Main Street or a Broadway, and that’s really the 1st Street 

Q: What was spray paint invented for?

A: It was to paint radiators initially, but it ended up with a lot of uses.

Q: Including creating graffiti, which you tried your hand at in Paris, correct?

A: I had lined up an interview. I was going to just talk to this guy and he said, “C’mon, let’s paint.” I wrote my name — Spike — in an alley.

It gave me such a sense of the scale of graffiti. As bad a rap as graffiti gets, there are lots of rules in that world. Most [graffiti artists] are respectful of the existing art, the work of true artists. And some of the art is amazing.

Q: Were you worried about getting fined or arrested?

A: A little bit. If you wind up in jail, that’s a good story, too.