Differences Between The Service And The Patrol

(i) The Service guards the future whereas the Patrol guards both past and future.

(ii) The Service avoids knowing the dates of any deaths whereas the Patrol knows many such dates.

(iii) The Patrol merely polices time travel whereas the Service monopolizes the Dirac communicator although one message, from March 12, 3022, is coded:

"'But why will we be using code?' Dr. Wald wanted to know. 'It implies that we think somebody might overhear us - somebody else with a Dirac. That could be very messy.'"

-James Blish, The Quincunx Of Time (New York, 1973), CHAPTER NINE, p. 104.

(iv) The Patrol conceals the fact of time travel before its invention and the Service conceals the source of its evident prescience. However, increasing numbers of people suspect the truth and are recruited into the Service.

(v) Time travellers can explore the further future whereas the Service must wait to learn the meanings of incomprehensible future Dirac messages.