POST OFFICE ENGINEERING DEPARTMENT — Technical Pamphlets for Workmen. [Group E]. COMPLETE SET IN ORIGINAL WRAPPERS

HMSO, 1928[-1938]. 3 vols., 8vo., with illustrations and diagrams in the text; original blue wrappers, wire-stitched as issued, covers lightly dust-soiled else a remarkably well-preserved, bright, clean set. The set comprises E1: Automatic Telephony Step by Step Systems; E2: Automatic Telephony: Coder Call Indicator (C.C.I.) Working; E3: Automatic Telephony: Keysending 'B' Positions. COMPLETE GROUPS OF THIS NOTABLE AND HISTORIC SERIES ARE RARE.