For what they are worth, you can find my reading notes for next week's seminar on Sections 2.5 and 2.6 of Logical Options here (they might help some students). Writing these notes has very much been displacement behaviour in the last day or two: I should really be preparing something on Ch. 4 of the Shorter Hodges for the model theory seminar this week, which I daftly promised to introduce. But heavens, that is not exactly an easy read. Gulp.