Field of interest in some future almanac (5)
I believe the answer is:
realm
'field of interest' is the definition.
(I've seen this before)
'in some future almanac' is the wordplay.
'in' indicates the answer is hidden within the clue.
'REALM' is hidden in the letters of 'some future almanac'.
(Other definitions for realm that I've seen before include "region" , "the UK, perhaps" , "Country" , "Area of influence" , "Royal domain" .)