The most common and most likely answer to this crossword clue is the 9 letter word EPIGRAPHS
I've seen this crossword clue in The Times
E
P
I
G
R
A
P
H
S
Buddy explains!
The straight part
We know that "introductory thoughts" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case introductory thoughts = epigraphs.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does EPIGRAPHS mean?
EPIGRAPHS noun- An inscription, especially on a building.
- A literary quotation placed at the beginning of a book or other text.
- (of a function) The set of all points lying on or above the function's graph.