After these loose histories, a more careful science developed. The real learning of the Arab scholars of the eleventh and twelfth centuries far outranked that of their European and Christian contemporaries. As yet the various fields of science were scarcely differentiated; the student took all knowledge for his province. The earliest Arab writer, who may perhaps be regarded as a genuine historian, in contrast to the previous romancers, was Al Biruni (973-1048), whose "Chronology" our volume quotes. But Al Biruni was far more than an historian; he was a leading scientist of his day and also a geographer, his work on "India" being almost as celebrated as his "Chronology." Of even greater fame in science than Al Biruni was Avicenna (980-1037), a sort of universal genius, known first as a physician. To his works on medicine he afterward added religious tracts, poems, works on philosophy, on logic, on physics, on mathematics, and on astronomy. He was also a statesman and a soldier, and he is said to have died of debauchery. He is famed as the most versatile and brilliant member of a versatile and brilliant race. With the increasing freedom of scientific thought and speech which Avicenna typifies, there sprang up among the Eastern Mohammedans a new religious impulse. They began to examine more carefully the faith which they had before accepted blindly. To this age therefore we owe the writings of Al Ghazali (1049-1111), whom some of his own countrymen have regarded as second only to Mohammed as a teacher of their religion. Indeed, it was a common saying of his day that "If there were still prophets in the world Al Ghazali would be one." Western scholars have, some of them, gone still further in their admiration of Al Ghazali, declaring him to have been one of the world's greatest thinkers, whom his Mohammedan contemporaries never sufficiently appreciated, and to whose high moral stature the Mohammedan world has not even yet grown up. Among his writings the most interesting and useful to modern readers is his "Rescuer from Error," a sort of spiritual autobiography, his account of his own growth in religious faith. This striking book our volume gives in full.