Portrait of Marlowe by Chandler

I have started reading this book again and in it I found a description of iconic private eye Philip Marlowe by his author Raymond Chandler which I found fascinating, for reasons which I will state below. Here it is:

"The date of his birth is uncertain. I think he said somewhere that he was 38 years old, but that was quite a while ago and he is no older today. He was born in a small California town called Santa Rosa about 50 miles from San Francisco. Marlowe has never spoken of his parents, and apparently he has no living relatives. I don't know why he came to Southern California, except that eventually most people do, although not all of them remain. He is slightly over six feet tall and weights above 13st 8lbs. he has dark brown hair, brown eyes, and the expression "passably good looking" would not satisfy him in the least. I don't think he looks tough, but he can be tough. If you ask me why he is a detective, I can't answer you..."

Chandler wrote this in a letter to an enquiring fan. So this descrption his fascinating for many reasons. Even in this letter, Chandler remains literary and evocative, it reads like a part of one of his novels. What is also just as interesting is the level of uncertainty: Chandler describes Marlowe physically in minimalist terms and is vague about his character's background. We get a better idea about his mindset, but even then it is more by evocation and the use of a few words than deep analysis. In sum, Chandler is writing here about someone he knows but not completely and not perfectly, rather than a character he created. So that is why I am obsessed about this quote. Now I want to find and read the whole letter.