Sidgwick's Introduction to Prose Composition in §18.
He describes the various types of conditionals:
1) If you are well, I am glad. εἰ εὖ ἔχεις, γέγηθα.
2) a. (Near or practical supposition). If you come, I shall come too. ἐὰν ἔλθῃς, ἀφίξομαι κἀγώ.
2) b. (Remote or speculative supposition). If I were to do it, I should be mad. εἰ τοῦτο δρῴην, μαινοίμην ἄν.
3) (Privative). If I had gone there, I should have found ...