In an earlier post, I was soliciting recommendations for texts to study since I cannot seem to get Cambridge University Press to respond to me. Paul Reiners suggested (amongst other things) Relation Algebras by Games by Hirsch and Hodkinson.
I went to the Math Library at the U of MN yesterday to look through it. I only had a quick glance since I had my 11-month-old in tow. As I am no longer staff or student at the U, I could not check it out. However, as I have a Hennepin County Library card, I am able to request it via Interlibrary Loan. Soon, I will have a chance to assess it more carefully.