Thanks for this, Kieran. Most of what he says is old news, but it's important to have it set out and studied in a systematic way, which hasn't happened before so far as I know. That makes his book sound exciting.
The notion of alternative endings has long been familiar: Euripides was an ironist, so his happy endings probably cut both ways, as in ALKESTIS, which we have. There's also a happy ending to the IPHIGENIA IN AULIS, which scholars say is probably spurious and was tacked onto the play a century or so later.
And we have the Euripides play in which Oedipus doesn't blind himself: The PHOENICIAN WOMEN. In that version his sons overthrow him and, as punishment for his crime, shut him up in a dark tower where he goes blind from lack of light. It's quite a crazy play & I've often wondered why nobody's tackled it in production.
Amazing that these plays written 2 1/2 millennia ago, for a theatre and a society unfathomably different from ours, still fascinate and in so many ways still seem to hold true. What a tribute to their authors.