There is no doubt that Blumentritt was the greatest, the number one, friend of Rizal. There is no doubt also that their friendship was as close and as intimate as any friendship between two human beings could be. Rizal considered Blumentritt as his father, brother and friend, while Blumentritt undoubtedly looked upon Rizal as his son, brother and friend. This friendship was shown in their letters which are preserved and collected in the Epistolario Rizalino. It is unfortunate that the collection is not complete. There are many missing letters. However, there are enough of them that can give the reader more or less a complete picture of the friendship that existed between the two.