I had read this years ago, but only remembered this after the rather silly ending of the last essay (set in 1982, with ex-President Allende inviting retired General Pinochet for a cup of tea). These ten alternate history essays were written in 1979. I think I bought the book for Owen Dudley Edwards' take on Gladstone in 1880, killing Irish Home Rule by enacting land reforms (which I don't see as very likely; the Home Rule genie was already out of the bottle by then).
There are two rather interesting essays exploring the potential for preventing the American War of Independence, one looking at how British policy might have been improved, the other imagining Benjamin Franklin facing down his own hard-liners and making peace in 1775. Both of these take as an important element the British decision to keep Canada rather than Guadeloupe in the 1762 peace negotiations. The arguments are 1) (counterfactual) that a continuing French presence to the north would have incentivised the British colonies of the eastern seaboard to stay in line with London, and 2) (factual) that the details of working out British administration in the newly acquired territory were destabilising further south. The two essays differ on the ultimate settlement - one has Britain and America continuing to be linked in union, the other imagines a more peaceful path to independence à la Canada in real life. But it is a successfully thought-provoking exercise.
Not so sure about the rest. We have four essays on regimes that might have survived if more statesmanship and shrewdness had been shown by their leaders - the French Empire in 1870, Kerensky in 1917, Dubcek in 1968 and as noted above Allende in 1972-3. These are interesting analyses of fatal mistakes made by rulers (admittedly in difficult circumstances) but not real alternative histories. Two others take the premise of German reunification in 1952, and the sparing of the life of Emperor Maximilian of Mexico in 1867, and fail to make either really interesting in terms of their consequences. I think the Maximilian question genuinely is a boring one, but more could have been done with Adenauer. Of course, that's easier to say now that German reunification has actually happened; when these essays were written in 1979 it was still unimaginable, though in fact only ten years away.
The most audacious of the essays is by Louis Allen, imagining that General Tojo called off the attack on the US planned for late 1941 and satisfied himself with the Dutch East Indies; and then joined with the Germans to defeat Russia; only in turn to be defeated when the Germans turned on them with American help. Tojo develops nuclear weapons and destroys San Francisco and Los Angeles, but still loses the war. I'm not particularly well versed in the history of the Pacific theatre, but it was an interesting read.