▁into ▁other ▁intelligence ▁assess ment ▁activities . ▁ ▁See ▁also ▁▁ ▁All - source ▁intelligence ▁ ▁Int elligence ▁cycle ▁ ▁List ▁of ▁intelligence ▁gather ing ▁discipl ines ▁ ▁Military ▁intelligence ▁ ▁Sur ve ill ance ▁ ▁Th re at ▁assess ment ▁ ▁Fut ures ▁studies ▁ ▁References ▁ ▁Further ▁reading ▁▁ ▁Sur ve ys ▁ ▁Andrew , ▁Christopher . ▁For ▁the ▁President ' s ▁E yes ▁Only : ▁Secret ▁Int elligence ▁and ▁the ▁American ▁Pres iden cy ▁from ▁Washington ▁to ▁Bush ▁( 1 9 9 6 ) ▁ ▁Black , ▁Ian ▁and ▁Morris , ▁Ben ny ▁Israel ' s ▁Secret ▁Wars : ▁A ▁History ▁of ▁Israel ' s ▁Int elligence ▁Services ▁( 1 9 9 1 ) ▁ ▁B ung ert , ▁He ike ▁et ▁al . ▁ed s . ▁Secret ▁Int elligence ▁in ▁the ▁Tw enti eth ▁Century ▁( 2 0 0 3 ) ▁ess ays ▁by ▁sch ol ars ▁ ▁D ul les , ▁Allen ▁W . ▁The ▁C raft ▁of ▁Int elligence : ▁America ' s ▁Leg end ary ▁Sp y ▁Master ▁on ▁the ▁Fund ament als ▁of ▁Int elligence ▁G ather ing ▁for ▁a ▁Free ▁World ▁( 2 0 0 6 ) ▁ ▁K ahn , ▁David ▁The ▁Code break ers : ▁The ▁Com pre h ensive ▁History ▁of ▁Secret ▁Communic ation ▁from ▁An cient ▁Times ▁to ▁the ▁Internet ▁( 1 9 9 6 ), ▁ 1 2 0 0 ▁pages ▁ ▁L erner , ▁K . ▁Lee ▁and ▁Br enda ▁Wil m oth ▁L erner , ▁ed s