The Thief's Journal by Jean Genet. Genet's most autobiographical work traces his years as a wandering criminal through Spain and North Africa in the 1930s. It has nothing directly to do with Larache — Genet came to the town much later in life — but it is the essential companion to understanding the man who chose to be buried here.
The Voices of Marrakesh by Elias Canetti. A short, piercing account of Canetti's visit to Morocco that captures the sensory texture of North African life better than most travel books. The Larache it describes is not Larache specifically, but Canetti's way of noticing — the sounds, the silences, the faces — translates directly to any Moroccan town.
Morocco That Was by Walter Harris. Harris was the Times correspondent in Morocco from the 1880s to the 1920s and witnessed the final decades of the old sultanate and the imposition of the French and Spanish protectorates. His account covers the northern towns, including the coast near Larache, with an outsider's eye that remains vivid more than a century later.