Hammond takes some time to explain the geography of ancient Greece – good material for those of us not intimately familiar with the Mediterranean climate. Useful tidbits concern the impact of geography on the economy:
p. 4: « These [mountainous] tracks, which are usually covered with forest and scrub or else eorded into barren precipices of limestone and marble, are sparsely populated, but they nevertheless play an important part in the economy of Greece. Above all, they provide the pastures which the lowlands cannot yield in the long summer drought. Large flocks of sheep migrate annually from the lowlands in April and May, and return from the highlands to the lowlands in the autumn. The uplands, too, support cattle, goats, and swine. Thus the mountainous tracks provide the meat and the milk products, which combine with the cereals, olives, fruit, pulse, and vegetables of the lowlands to form a balanced diet. The mountains also supply timber for fuel and for building, including pine, cedar and cypress for ship-construction and the valonea oak for dye, pig-fodder, and tanning extract. »
Hammond also makes the point (p. 9) that all regions of Greece (he calls them cantons) are fairly self-sufficient, having mountainous, fertile plains and coastline zones. This self-sufficiency encourages the formation of many autonomous polities.
Of course (and Hammond gets to that later), the large Greek cities need to import food from elsewhere (grain from the Caucasus and Egypt for instance) to sustain their excess population. This commerce comes in handy when your polis sees its field ravaged by an enemy in the endless conflicts between the many small polities. This works well as long as you have a fleet to patrol the seas. It worked well for Athens during the Peloponnesian War. Not so well for Megara, whose ports were under surveillance by the Athenian fleet.