Darko Suvin has an idiosyncratic style that is both strength and weakness. A strength, because he brings decades of experience and deep philosophical understandings to his examination of Yugoslavia's unique system of workers' self-management. A weakness because the book is not as focused as it should be with a non-linear style in which some of the most important material is left for a second appendix rather than being integrated with the main text.
Idiosyncrasies aside, this is a valuable book well worth reading for any student of Yugoslavia. The author examines the question of why the system of workers' self-management ultimately collapsed from a domestic perspective. There are no more than a handful of passing mentions of external factors, such as the country's increasing integration into the world capitalist system and mounting external debt, nor the austerity the International Monetary Fund would ultimately impose on the country. This is an omission that matters because these external factors are a significant portion of this story.
Nonetheless, the author's mastery of internal affairs, how what he terms a "class" arose within the top layers of the communist party, integrated with the top managerial layers, that came to see its interests as more inequality and more authoritarianism. This process was greatly accelerated by the fragmentation of party and economy into a collection of republic fiefdoms, helping unravel the economy as each republic leadership created its own separate ruling structure, consolidating the rule of these local leaders and perpetrating inequalities among the republics. And the dichotomy of workers' self-management with an original goal of allowing everybody to take part in decision-making on the one hand, and a party that consistently maintained a monopoly of political power on the other hand, could never be solved and couldn't be solved.
Splendour, Misery, and Possibilities argues persuasively that what Yugoslavia needed was a full turn to self-management as part of a full democratization of politics and economics, and skillfully explicates the thinking of leading party officials and prominent philosophers, including critical voices advocating a dismantling of political monopoly, in presenting a learned and readable history of Yugoslav self-management up to the early 1970s.
Some will, as I do, disagree with the author's strong insistence that the elites who benefited from political monopoly and the usurpation of managerial decision-making constitute a class. The assessment of the elites as a separate, exploiting class originally arose with Milovan Djilas in the 1950s, but the historian Isaac Deutscher thoroughly dismantled that argument. To be fair, Darko Suvin's argument for calling the elites a class is much more sophisticated than Djilas', and he does make his case well. Whether "class" or "strata" is your preference, this in no way detracts from the very high level of sophistication and analysis that pervades the book.
If you are interested in understanding how Yugoslavia first flourished but ultimately collapsed, you will want to read this book.