Hi, The ‘ O ’ in of is not capitalized because of is a preposition, and prepositions are not capitalized in titles unless they are used adjectivally or adverbially. Similarly, and, in and articles are not capitalized. However, you should capitalize the first word of the title, the last word of the title, verbs, nouns, pronouns, adverbs, adjectives, subordinating conjunctions, and a few conjunctions Regards
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