The Dulcimer Book by Jean Ritchie
Dulcimer Resources:TABS/Books/websites/DVDs
Bill, this book was written at a time when dulcimer 'tab' was not that common yet- and a higher percentage of players knew how to read music a little. This issue is one small drawback of this particular book.Here's how I figure it out:First I look at where it tells me what MODE the song is in for the book- In the beginning of the book there is an index of songs and their modes.For example, Aunt Rhodie is in ionian mode, Jean states there.Then I go to the song itself, and I look at the fret the song ends in. In this case, fret 3....thus confirming ionian mode.Now, if you happen to know that DAA tuning as an ionian tuning, you could just stop right there and tune to DAA and follow the fret numbers in Jean's tab and all will be well.

But say you want to know which ionian tuning she uses, or what key she has chosen?Well if you look closely at the song, on the left top of the song it says "Tune dulcimer..." and underneath that it gives three whole notes indicating the three notes to tune your three strings.The lowest note will be your bass string.Look at this chart:
http://www.cyberfret.com/reading/converting-standard-notation-to-guitar-tablature/1st-position.html Ignore the guitar tab part, just look at the named notes on the music staff.Do you see the first C note, and where it is located on the staff of lines? You will see that Jean's BASS low note is on that same low line. So Jean is tuning her bass string to C. Jean's other two notes she writes un er (Tune dulcimer..." are G notes, if you look at the note chart and compare. Thus, jean is tuning her dulcimer to DGG, which is the typical ionian tuning for the key of C.If you print that note chart out, it can help you figure things out when confronted by these frustrating mysteries.Another example is Shady Grove in jean's book. She states in the song list that it's aeolian.Then look at where she places the low bass string under 'tune dulcimer', and look at the note chart- it's a C note again. Then look at her middle string indication under 'tune dulcimer' (the note in the middle)- again it's a G. Now look at her highest note for tuning the strings, and look at the lower chart to find it- it's a B flat (flat is the little "b" indication).So, for shady grove, Jean is tuning C-G-b flat.CGb-flat is the key of C version of what we usually see for aeolian key of D....D-A-C tuning. All strings are simply one whole step down from DAC, and going from key of D to key of C.Again,
just knowing that she tabs it in aeolian mode from the first Song List at the beginning of the book would then tell you you can simply tune in any aeolian tuning, such as DAC, and be able to play the same tab and same tab numbers.I know this sounds complicated, but the notation charts can help you determine what some notes are.