For years, I've thought about "that letter"!! Happy to see I'm not the only one---Grissom didn't send it because Sara was getting her mail at the lab. He had already sent her a package (or was it later?) Anyway, for Sara to get two pieces of mail from him, her supervisor, would probably arouse suspicious minds--why was he sending her mail? So, he decided against it. Yet, later, he wanted her to have the letter. He put it inside a book on her side of the bed--perhaps to surprise her with his written words since he wrote he had difficulty saying some things to her!! Thanks for bringing this up---such great episodes!