Welcome To Mars III

Jack Loftus stars in The Star Dwellers and in its immediate sequel, Mission To The Heart Stars;

Adolph Haertel stars in Welcome To Mars and appears in "Common Time," the first of three connected short stories in the collection, Galactic Cluster;

Thor Wald appears in The Quincunx Of Time and is referred to early in Midsummer Century.

Thus, there are three instances of two volumes linked by one character. Loftus and Wald also refer to Haertel but only in the same way as they refer to Einstein.

Haertel:

was introduced in "Common Time";

became a historical character common to alternative futures inhabited by Loftus, Wald and others (Arpe in "Nor Iron Bars" and Ruiz-Sanchez in A Case Of Conscience);

then, in a third and final stage, was adapted as the teenage hero of the juvenile novel Welcome To Mars - although we might ask whether this younger Haertel is quite consistent with any of the various older versions.

Mission To The Heart Stars was written after The Star Dwellers;
Galactic Cluster was written before Welcome To Mars;
Midsummer Century was written while "Beep" was being expanded as The Quincunx Of Time.

Non-technical readers usually trust the scientific information imparted in works of hard sf. In Welcome To Mars, we:

(i) understand that Haertel, in this work called "Dolph," has the urgent problem of how to survive indefinitely when marooned on Mars;

 

(ii) soon come to accept that he has solved this problem;

(iii) might come to wonder whether we have been given enough information to warrant the transition from (i) to (ii).

The information is there but maybe, for some of us, needed to be spelled out a bit more. More on this later. (See here.)