Four chapters narrate the origins, heyday, and decline of Spanish transhumant herding. The Philips suggest that royal intervention was actually reasonably even-handed, balancing the competing demands of different factions and of agriculture and pastoralism, and that much of the decline in transhumant herding was due to a shift to local herding. They also cover topics such as the spread of the Merino outside Spain.
Part II describes the mechanics of dogs and shepherds and tame wethers with bells and the annual cycle of transhumance. After shearing finished in late June, flocks moved to summer pastures across northern Spain; in autumn, typically in September after rains began, came the trek to winter pastures in the central Meseta of Castile or in the south in Extremadura, La Mancha, and Andalusia; lambing happened from late November through December; and around April the trek to shearing places began. Separate chapters describe the shearing of the flocks and the washing of the fleece.
Part III turns to the wool trade and marketing, with a focus on the merchants of Burgos. It covers the internal market, textile manufacturing, and the transport of wool by land and sea, especially the routes from the interior to the north coast and shipping from there to North-Western Europe. The wool trade created extensive trading networks overseas; here the focus is on the Consulado of Bruges, the largest Spanish merchant community abroad. A final chapter attempts to extract, from the often patchy evidence, figures for wool production, prices, and exports over the period.
The topic is reasonably specialised, but Spain's Golden Fleece is not over-technical: most of the tables are left to appendices and the discussion of sources to a hundred pages of endnotes. Anyone curious about medieval technology or economic history should find it fascinating.