than BELL and BEST, the Station personnel only know BERTRAM as someone authorized to be in the Station, and who is known for his piano playing at embassy parties. He is as Cultural Attache, in a country that has very few pianos. Only the personnel involved with BARD know that ARNOLD is other than another diplomat. In contrast, BESSIE and BETTY know one another, and procedures exist for their taking over each other's assets in the event one of the two is disabled. Some recruits, however, would be qualified to recruit their own subcell, as BEATLE has done. BETTY knows the identity of BEATLE-1 and BEATLE-2, since he or she had them checked by headquarters counterintelligence before they were recruited. Clandestine presence The diagram in this section shows that two teams, ALAN and ALICE, have successfully entered an area of operation, the country coded AL, but are only aware of a pool of potential recruits, and have not yet actually recruited anyone. They communicate with one another only through headquarters, so compromise of one team will not affect the other. Assume that in team ALAN, ALASTAIR is one of the officers with local contacts, and might recruit two cell leaders: ALPINE and ALTITUDE. The other local officer in the team, ALBERT, recruits ALLOVER. When ALPINE recruited two subcell members, they would be referred to as ALPINE-1 and ALPINE-2. ALPINE and ALTITUDE only know how to reach ALASTAIR, but they are aware of at least some of other team members' identities should ALASTAIR be unavailable, and they would accept a message from ALBERT. Most often, the identity (and location) of the radio operator may not be shared. ALPINE and ALTITUDE, however, do not know one another. They do not know any of the members of team ALICE. The of the subcell structure came from the recruitment process, originally by the case officer and then by the cell leaders. The cell leader might propose subcell member names to the case officer, so the case officer could have headquarters run a background check on the potential recruit before bringing them into the subcell. In principle, however, the subcell members would know ALPINE, and sometimes the other members of the ALPINE cell if they needed to work together; if ALPINE-1 and ALPINE-2 had independent assignments, they might not know each other. ALPINE-1 and ALPINE-2 certainly would not know ALASTAIR or anyone in the ALTITUDE