From the Back of the Book:

William Thomas Walsh was a prolific Catholic writer on various aspects of Church history and personalities. 

This book is on the Inquisition, particularly the Spanish Inquisition as opposed to the Roman Inquisition in the years following the Spanish Reconquista. Walsh delves into the Inquisition, its practice, purpose, history and personalities. 

Anyone wishing to understand the Inquisition would do well to read Characters and learn of the heroes of the Faith, Cardinal Ximenes, Torquemada, and others who fought the good fight for Jesus Christ and his Church.

After reading Characters, you will never look at the Inquisition the same.