How to improve my sentences/grammer?

I need help improving my grammer/sentence structure. It would be helpful, if someone can walk me through it. It would help me next time i write a book review.

Three Cups of Tea by Greg Mortenson and David Oliver Relin is an adventurous novel in which, Greg Mortenson a mountaineer strives to provide an education for those less fortunate to obtain one in the poor villages of Central Asia.

During the 1990s, Greg Mortenson attempted to climb K2, in the Karakoram Range of northern Pakistan. After becoming lost during the climb of more than fifty days, Greg Mortenson exhausted and weak ends up in Korphe, a small village built on a canyon. He is spotted by the chief, Haji Ali who takes Greg in and recovers him from his exhaustion. To repay the village for its hospitality, Greg promises to build a school for the village after returning to America and collecting the funds for the labor and materials. As Mortenson reaches America, he is faced with challenges such as poverty that might question his promise to complete the heroic mission.

Relin begins the story by introducing the reader to Mortenson’s obstacle while climbing the “Savage Mountains” of northern Pakistan. Indirectly, Relin indicates Mortenson’s uncertainty of his own future. In sequence, Relin introduces two flashbacks, involving Mortenson‘s charitable nature. The first flashback takes the reader in an insight of Mortenson’s personal life; where he nurses his ill sister. The second describes his efforts to rescue a fellow climber. These analytical aspects reveal Mortenson’s instinct to help others, and foreshadow his future. Mortenson’s idealistic view of education in civilized countries, contributes to the driving factor towards, “fighting a war on terror with education.” Thus, Mortenson and Relin synthesize the effects of education on an uncivilized society.

I enjoyed reading this book, because of the thrilling outcomes of Mortenson’s adventure which deeply questioned his undaunted actions. Mortenson and Relin thoroughly compare the villagers and their reactions to what they thought about Mortenson. This adventure included limitless suspense, which entitled me to continue reading. Overall, this book was excellent, discounting the repetition included during Mortenson’s adventure. I recommend this to anyone that enjoys reading about a sad and thrilling adventure of one brave man.

Thank you.