[bluishgreen]

"JavaScript relies heavily on callback functions: Instead of a function giving us a result immediately, we give it another function that tells it what to do next. Many other languages use them as well, but JavaScript is often the first place that programmers with data science backgrounds encounter them."

That sentence from the book clarifies a lot for me. It is Javascript for Data Science People. Taken in that context this is an excellent book written with empathy for the Data Science user who is usually making uneasy excursions which they hope and pray is only temporary into Javascript and running back to Python the first time they encounter a Promise or a Callback.