The Future Patrol

Contradiction:

"...in the year 19352 A.D....men would find a way to travel through time..." (Time Patrol, p. 6)

"The thirty-first millennium was...is far earlier than the development of the first time machines..." (p. 660)

Solutions:

the second passage is thought by Stephen Tamberly who may be mistaken;

the real situation may be as follows -

(i) the discovery of time travel;
(ii) the founding of the Patrol;
(iii) the Patrol ceasing to conceal its existence and beginning to operate openly.

I suggest that, in the timeline defended by the Patrol, (i) and (ii) are simultaneous but (iii) is later.

Incidentally, Tamberly also reflects that Temporal has not only tenses but also verbs to deal with time travel - and that exhausts our knowledge of the language. We see an agent in place on the Moon in 2319 - and that exhausts our knowledge of the Patrol post-twentieth-century. The futuristic framework of the series was merely a device for Poul Anderson to write superb historical sf.