Where to begin reading about steam machinery in warships

Which books help explain steam boilers and machinery in warship design?

Start with broader design histories such as The Pre-Dreadnought Revolution, D. K. Brown's Warrior to Dreadnought, and Norman Friedman's works.

No strong boiler-only volume is identified from the books at hand. The recommendation turns instead to design histories that place machinery in context: Warren Berry's The Pre-Dreadnought Revolution, D. K. Brown's Warrior to Dreadnought, and the relevant works of Norman Friedman. These books let readers study propulsion alongside hull form, armour, armament, and the wider evolution of sea power.