Titles - capitalisation
There is one rule about capital letters in the titles of books or other works such as films, paintings, plays, and other resources in normal academic English writing: put the first letter of any form word in upper case. (Form words are in essence nouns, verbs, adjectives and adverbs.) Function words - the 'small' words like 'the', 'of' and so on - are not normally capitalised.
This rule holds good in most academic writing. It is varied in various special forms, such as library catalogues, bibliographies and booklists.
A separate convention often applies to subtitles. These should normally be written with a colon after the main title, and with no capitalisation except for proper nouns, which should be marked in the usual way.
You may also want to see Titles and Titles - italicisation.