The Links In The Time Patrol Series

One early chapter of Poul Anderson's The Shield Of Time is a flashback to the events of "The Year Of The Ransom." Another early chapter is a flashback to the events of "Ivory, And Apes, And Peacocks." Thus, the Exaltationist villain, Merau Varagan, makes a third appearance despite having been apprehended in "...Peacocks." Thus also, these two stories link Time Patrol to The Shield Of Time.

After the opening sections of The Shield Of Time, the two questions to be answered are:

What becomes of Wanda Tamberly, introduced in "...Ransom," in her Time Patrol career?

What threat might still exist after the last Exaltationists have been apprehended?

Anderson invents a major crisis for Wanda in prehistory and conceptualizes an original answer to the second question. Even when there are no time criminals, random fluctuations in space-time-energy can violate causality and the counteraction of such temporal chaos is the real purpose of the Patrol.

The series developed an elaborate internal structure that went far beyond its humbler beginnings in the original short tetralogy of Guardians Of Time.