What do “breakout hit” and “have a finger on the pulse of” mean?
“This heartfelt memoir was... a breakout hit and one of the most discussed titles of the year... There’s no denying Vance has a finger on the pulse of white poverty in Appalachia and the Rust Belt.“ - Praise for the book “Hillbilly Elegy” from “Atlanta Journal”

What do “breakout hit” and “have a finger on the pulse of” mean here?

Question

What do “breakout hit” and “have a finger on the pulse of” mean?
“This heartfelt memoir was... a breakout hit and one of the most discussed titles of the year... There’s no denying Vance has a finger on the pulse of white poverty in Appalachia and the Rust Belt.“ - Praise for the book “Hillbilly Elegy” from “Atlanta Journal”

What do “breakout hit” and “have a finger on the pulse of” mean here?

Answer

breakout hit - a very successful work of art (movie, book, song) that moves somebody from obscurity to fame

finger on the pulse - being up to date/knowing what going on with a subject, group of people, etc. The subject is generally in a state of flux. (One can't have one's finger on the pulse of ancient Greece.)

Answer

I think a "breakout hit" is something that is wildly successful and brings immediate fame to the author. To have a "finger on the pulse" of something is to understand it well. In this case it would mean the author understands people living in that region and has created very realistic characters.