For a detailed understanding of the Catholic Church's efforts to protect orthodoxy, especially during the time of the Crusades and the acquisition of knowledge from Islamic sources, several books and resources can provide valuable insights:
"A History of the Inquisition of Spain" by Henry Charles Lea - This comprehensive book covers the origins, establishment, and evolution of the Spanish Inquisition. It delves into the Church's strategies to suppress heretical ideas and maintain religious orthodoxy during a period when knowledge from various cultures, including Islamic scholarship, was spreading into Europe.
"The Origins of the Inquisition in Fifteenth Century Spain" by B. Netanyahu - This work focuses on the establishment and impact of the Inquisition in Spain, offering insights into how the Catholic Church reacted to perceived threats from newly introduced knowledge and ideas.
"Montaillou: Cathars and Catholics in a French Village 1294-1324" by Emmanuel Le Roy Ladurie - Although this book primarily examines the Cathar heresy in France, it provides a perspective on the broader religious and ideological conflicts in medieval Europe, which were also influenced by the spread of non-Christian knowledge.
"All Can Be Saved: Religious Tolerance and Salvation in the Iberian Atlantic World" by Stuart B. Schwartz - This book looks at the diversity of religious beliefs in the Iberian world and the Church's efforts to regulate orthodoxy, especially in response to challenges posed by different religious ideas.
These books provide a historical context for how the Catholic Church utilized methods like the Inquisition to censor and control the spread of knowledge that contradicted its teachings, particularly after exposure to Islamic scholarship from Al-Andalus and the influence of returning Crusaders. For a broader look at the topic of censorship, you can also refer to the article on the Index Librorum Prohibitorum in Britannica, which discusses the Church's list of banned books and other efforts to curb heretical ideas.
For more recommendations on books about the Inquisition, you can explore this list of suggested readings on the subject: The Best Books on The Inquisition​