Transport physics in the divertor and scrape-off layer of Alcator C-Mod is investigated for a wide range of plasma conditions. parallel (parallel to) transport topics include: low recycling, high-recycling, and detached regimes, thermoelectric currents, asymmetric heat fluxes driven by thermoelectric currents, and reversed divertor flows. Perpendicular (perpendicular to) transport topics include: expected and measured scalings of perpendicular to gradients with local conditions, estimated chi(perpendicular to) profiles and scalings, divertor neutral retention effects, and L-mode/H-mode effects. Key results are: (i) classical parallel to transport is obeyed with ion-neutral momentum coupling effects, (ii) perpendicular to heat transport is proportional to local gradients, (iii) chi(perpendicular to) proportional to T-e(-0.6) n(-0.6) L-0.7 in L-mode, insensitive to toroidal field, (iv) chi(perpendicular to) is dependent on divertor neutral retention, (v) H-mode transport barrier effects partially extend inside the SOL, (vi) inside/outside divertor asymmetries may be caused by a thermoelectric instability, and (vii) reversed parallel to flows depend on divertor asymmetries and their implicit ionization source imbalances.