Galdos wrote prolifically in two distinct narrative modes: some twenty major 'contemporary novels' in the realist tradition and a special sort of historical novel he called the episodio nacional. The reign of Isabella II (1843-68) and the revolutionary period which followed until 1875 was a time of exceptional volatility in Spain, and Geoffrey Ribbans's comprehensive study shows how each of Galdos's two narrative modes adopts a particular technique in its treatment of Spanish history and politics. The episodio is tightly bound to historical events and timescale, though it skilfully incorporates its fictional characters into this framework; the novel on the other hand is embedded in historical reality in a constant but less systematic manner.