The most common and most likely answer to this crossword clue is the 10 letter word HISTORIANS
I've seen this crossword clue in The Daily Telegraph
H
I
S
T
O
R
I
A
N
S
Buddy explains!
The straight part
We know that "They look back" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case they look back = historians.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 HISTORIANS mean?
HISTORIANS noun- A writer of history; a chronicler; an annalist.
- One who studies or researches history.
- One who recounts their own medical history.