TITLE: Would it make sense to have someone write separate teaching and non-teaching letters of reference for one candidate?
QUESTION [10 upvotes]: 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?

REPLY [6 votes]: This is a reasonable thing to do, and is definitely possible in mathjobs--indeed, I believe that we have just offered a job to an individual whose mathjobs-based application had distinct research and teaching letters from the same person.  He also had a teaching letter from someone else, as well as a surplus of research letters, consistently with Pete's advice.  
I'm not sure how this worked on the letter-writer's end, but on our end the only difference is that there are two files next to the letter-writer's name rather than the usual one.  The modifier "(teaching)" which usually appears next to the name of the authors of teaching letters, does not appear next to the name of the letter-writer in question--though maybe this is only because it is quite generally the case that you're only allowed to specify one person as your teaching reference,* and the applicant would have specified the author of the other teaching letter.  
*I don't remember whether this is true, but looking at other applications with two teaching letters suggests that it is.