The most common and most likely answer to this crossword clue is the 10 letter word BARONETAGE
I've seen this crossword clue in The Times
B
A
R
O
N
E
T
A
G
E
Buddy explains!
The straight part
We know that "all Jane’s Sir Walter would read?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case all jane’s sir walter would read? = baronetage.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 BARONETAGE mean?
BARONETAGE noun- Baronets collectively
- The rank of a baronet