These are the most frequently used words in this book.
2001
action
afghanistan
against
agencies
agents
air
aircraft
al
american
another
atta
attack
authority
between
bin
binalshibh
call
case
center
chief
cia
civilians
clarke
command
committee
counterterrorism
country
day
defense
department
director
during
early
efforts
even
evidence
faa
fbi
first
flight
floors
force
general
government
group
hazmi
hijackers
house
including
information
intelligence
ksm
ladin
later
may
members
might
mihdhar
military
national
new
north
office
officers
officials
operations
operatives
pakistan
part
plan
plane
possible
president
qaeda
report
response
saudi
secretary
security
september
service
should
south
states
system
taliban
terrorism
terrorist
threat
time
told
tower
training
two
united
units
war
world
years
