Each sentence combines the plots or characters of two different books with numbers in their title. The numbers in the title replace their authors' last initial(s) in the given equation to yield a number that can be converted to a letter:

Clue | Book 1 | Book 2 | Equation | Number | Letter |
---|---|---|---|---|---|

Guy Montag burns Shelob to save Frodo. | Farenheit 451 | The Two Towers | log_{3}(log_{2}(451+61)) | 2 | B |

This book chronicles many generations of the Buendía family in London after being released from the Bastille. | One Hundred Years of Solitude | A Tale of Two Cities | sqrt(100)/2 | 5 | E |

The Tralfamadorians capture Athos, Porthos, and Aramis and put them in a zoo. | Slaughterhouse-Five | The Three Musketeers | 3*5-1 | 14 | N |

Captain Nemo helps liberate Arabia from the Ottomans. | Twenty Thousand Leagues Under the Sea | Seven Pillars of Wisdom | (7!*4-20000)/10-5 | 11 | K |

Sherlock Holmes investigates accusations of witchcraft in a home in Salem, MA where Major Sholto stashed his stolen treasure. | The Sign of the Four | The House of the Seven Gables | (7*4-1)/(7-4) | 9 | I |

Every time Yossarian tries to remove his cap, another one appears. | Catch-22 | The 500 Hats of Bartholomew Cubbins | 500-22^{2}-2 | 14 | N |

Winston Smith is captured and sold to William Prince Ford. | Nineteen Eighty-Four | Twelve Years a Slave | (1984-12*100)/(12+100) | 7 | G |

The true confessions of Cruela de Vil turned out to be a lie, and were denounced by Oprah. | The Hundred and One Dalmatians | A Million Little Pieces | (1000000-101^{3}+3*101^{2}-2*101-5)/5 | 19 | S |

Pooka MacPhellimey befriend Laila in Kabul. | At Swim-Two-Birds | A Thousand Splendid Suns | ceil(log_{2}(1000))+2 | 12 | L |

A boy circumnavigates the globe while on a lifeboat with a tiger. | Around the World in Eighty Days | Life of Pi | sin(pi/4)^{8}*80 | 5 | E |

The "true north" principles described in this book include disguising mailboxes as waste bin | The 7 Habits of Highly Effective People | The Crying of Lot 49 | (49+1)/log_{7}(49) | 25 | Y |

The answer is therefore **BEN KINGSLEY**.