There's a friend of mine (seriously, not me) who is facing a slight dilemma. There's a particular senior mathematician who he knows well (several co-authored papers, etc.) who also is probably the person best placed to comment on his teaching abilities. Now, of course, this sounds very convenient; after all you can roll lots of praise into one letter, right?
But there's an issue with this: I know for a fact that many people on search committees don't read the letters that are supposed to concern teaching. Certainly, many will not to read them until one has gotten down to a fairly short list. So you don't necessarily want lots of praise for your accomplishments in general to be in a letter which has "(teaching)" next to it on MathJobs. I'm trying to think of what to suggest to my friend as a way out of this dilemma, and one idea which floated to the top of my mind was this: maybe this senior person could write two separate letters, one for teaching and one for everything else. Is this an insane idea? Is there some better way out of this dilemma?