Under lock and code use electronic modular access units (EMAUs) — sets of secure compartments to hold patrons’ requested materials — as part of a remote, web-enabled library materials delivery system. The EMAU is accessed by an electronic keypad with an LCD display and/or optional card reader that unlocks the compartments. Patrons can retrieve their materials 24/7 using codes up to seven digits or with a card issued by the library. Remote administration from the library is available as well as manual key override, pass-through doors, and a courier mode that allows a courier to open all compartment doors simultaneously for faster stocking. Various configurations are available to customize size and number of compartments to client needs.