Here are a few titles I would recommend:

"District Tartans" by Gordon Teall & Phillip Smith

"Tartan: the Highland Textile" By James Scarlett*

"The Illustrated Encyclopedia of Tartan" by Iain Zaczek

*Scarlett has a number of smaller booklets on the history of various tartan "groups", such as military tartans and tartans of specific clans. Many of these can be purchased through the Scottish Tartans Authority.

I haven't examined our own Matt Newsome's new compendium of District Tartans, but given Matt's reputation, I am sure it is "top-notch" in research & presentation.

Cheers,

Todd