postal   service. Transportation  within  the domestic   system   is   by   airlift   or   expedited surface   delivery.   Official   First-Class   Mail   is normally sent by commercial air transportation from  the  continental  United  States  to  overseas areas  of  delivery  when  addressed  to  an activity  with  an  FPO  or  APO  address. REGISTERED   MAIL Registered  mail  receives  added  protection because  of  its  value  and  importance.  It  is  the safest  means  of  any  mail  service  since,  from the  time  a  piece  is  mailed,  someone  is  always personally  responsible  to  account  for  it. The   postal   service   provides   the   sender with a receipt and an identification number for each  article  received. The   identification number  is  also  placed  on  the  item  at  the  time of  mailing  and  is  used  throughout  the  delivery process. A  continuous  chain  of  receipts  is maintained  by  each  person  who  handles  the article.  The  person  who  signed  the  receipt last  is  responsible  for  the  item  until  a  receipt is  signed  by  the  person  to  whom  the  article  is addressed. The   post   office   that   services   your command  provides  an  incoming  and  outgoing registered   mail   log. If  this  log  is  used properly,  it  will  help  you  to  pinpoint  the  date a  specific  piece  of  mail  was  sent  or  received. It  should  include  the  registered  identification number,   identification   of   the   subject   matter, the  addressee,  and  the  signature  of  the  person receiving  the  material  from  you.  The  Security Manual  and  chapter  8  of  this  training  manual provide   more information   on   how   the registered  mail  system  is  used  to  transmit classified   information. EXPRESS   MAIL Express  Mail  is  the  class  of  mail  afforded the  highest  priority  in  handling  and  provides highly  reliable  service.  Use  Express  Mail only  when  it  is  the  most  cost-effective  way  to accomplish  a  mission  within  time,  security, and   accountability   constraints.   Heads   of   the Department  of  Defense  are  authorized  to approve  the  use  of  Express  Mail. Tenant commands  must  request  approval  from  the host installation to use Express Mail when the host  provides  the  postage  and  fees  for  the tenant’s mail. CERTIFIED   MAIL Certified  mail  is  a  postal  service  that provides  the  sender  with  a  mailing  receipt.  A record  of  delivery  is  kept  at  the  post  office. Service  is  limited  to  First-Class  mailing  of material   requiring   restricted   delivery. The sender  is  given  a  receipt  and  a  record  is  made of  delivery  to  the  post  office.  The  addressee completes   a record of   delivery that accompanies  the  piece  of  mail  which  is  then returned  to  you. CLASSIFIED   MAIL Chapter 8 of this training manual gives the procedures  for  processing  classified  material. HANDLING   INCOMING   MAIL You  may  be  assigned  to  handle  incoming mail  in  any  department  or  office  to  which  you are  attached.  In  a  departmental  office  aboard a  ship  such  an  assignment  may  not  involve  a very  large  amount  of  mail,  but  if  you  are  in the  captain’s  office,  you  will  be  handling  all the  official  mail  for  the  ship.  In  any  case,  it is  important  that  you  know  what  happens  to incoming   mail. The  volume  of  mail  received  by  naval activities today makes it desirable to eliminate unnecessary  operations  wherever  possible.  In doing  so,  however,  it  is  important  to  make sure   adequate records   of   all   important correspondence   are   maintained.   Experience and judgment are required to determine which mail  need  not  be  controlled,  which  should  be controlled,  and  how  the  necessary  controls  can be  maintained. 4-2