Book Title Quiz

[Fleur2013]

I am stuck on this question from the Macmillan cancer quiz. 'Ruler of no. 80?' The answer to no. 80 is Planet of the Apes. The answer is a book title. Thanks for any ideas

[mallyh]

gorillas in the mist?

[vakayu]

Caesar?

[Fleur2013]

Sorry, I forgot to give number of letters (6,2,3,4)

[dannyk13]

If it helps the Planet of the Apes was Earth

[grasscarp]

Tarzan of the apes

[aelmpvw]

caesar was the ruler of the apes

[dannyk13]

Leader Of The Pack (Kate Cann) ?

[vakayu]

Planet of the apes fits those letters?

[Baldric]

That ^^^ letter pattern looks like 'Planet of the Apes'

[grasscarp]

It has to be Tarzan of the Apes.
The book tells how he became King of the Apes.

[dannyk13]

As Planet of the Apes is mentioned in the clue I do not think it will also be the answer.

[dannyk13]

Grasscarp's answer looks the most plausible.

[Fleur2013]

Thank you!