The most common and most likely answer to this crossword clue is the 8 letter word ATLANTIS
I've seen this crossword clue in The Guardian
A
T
L
A
N
T
I
S
More clues leading to the result ATLANTIS
- Unfinished map book isn’t distorting sunken land
- Books one found amongst maps for city below sea level
- Island not traced? It's given name, turning up in map book
- Lost land from biblical books, one in mountain range
- Lost realm of New Testament, one shown in map book
- Having reached 50, worker lives in fantasy land
- At length, opponents destroyed continent
- What can be seen in book of maps? Not this island, for starters!
- Titan carries books on island, a legendary one
- Lost civilisation identified by books I found in mountains
Buddy explains!
The straight part
We know that "long-lost land/long-lost land" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case long-lost land/long-lost land = atlantis.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.