Found: YA SF Dimensional ‘Sliders’ Plot; teenage boy seeks his father lost in the alternate worlds.

I read this novel in the late 60s or start of the 70s borrowed from a British public library, so it cannot be newer than this. A late teenage somewhat shy male protagonist discovers his father has invented a dimension sliding device for travelling to alternate reality Earths, gone exploring and failed to return. He resolves to find his father and with the aid of an adult companion (? Or of contemporary age) who insists that he must lose his shyness for this to be successful, given he will encounter many people he will need to explain himself and ask for assistance. He then uses another copy of the same device (a harness with a belt) to go after his father. The dimension shift is triggered by turning a ‘rheostat’ (I knew enough electronics at that age to know this to be a older term for what I would have called a potentiometer or variable resistor, like the volume control on a radio of the time) affixed to the belt which resets itself with a click once the ‘jump’ is complete. The story had the two common tropes used in all alternate reality travelling plots I have encountered. The first is that the device must recharge (its capacitors or whatever) for a plot-dependent time so that on arriving in a hostile environment, the main character(s) cannot just leave immediately, thus ensuring he/they have to make the best of the situation somehow for a period of time. The second trope is that the main character(s) cannot just go back home, hand-waved away with some techno-speak appropriate to when the story was written (e.g. 1970s ‘the n-dimensional subspace manifold branches become tangled when travelling between them’ or some such) so are forced to continue exploring.

I only really remember two of the alternate realities. In one, a new Ice Age appeared to cover the Northern Hemisphere and the protagonist (I don’t remember any companion here) had to enlist the aid of the locals to avoid hypothermia. I recall the leader of the tribe ordered another tribal member to hand his cloak to the protagonist to wear. This person then had to run back to the tribal village bare-chested to obtain protection for himself, demonstrating their physical toughness and cold resilience.

In the second alternate world, the protagonist found himself in a technologically-advanced utopian society and discovered his father had been here but had since moved on to another alternate. While benign, the protagonist felt that there was something missing in this culture; too focused on technology and insufficiently on human values. In particular, though aware of the technology of dimension sliding, they felt it too dangerous to go exploring it so clearly they lacked any sense of adventure. Moreover, they understood the science behind it well enough to warn him that finding a way home to his alternate would be very difficult (? Or impossible).

If I recall correctly, the protagonist was able to find his father and he agreed that the advanced technology alternate world they both had visited was not a suitable stopping point. I just can’t remember if the reunited father and son continued exploring together or instead settled on a world a bit more like our Earth with fewer problems than we have. This is the limit of what I can remember.

The Infinite Worlds of Maybe, by Lester del Rey? https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&c...

Touchstone The Infinite Worlds of Maybe by Lester del Rey.

>2 sueelleker: Yes. Thank you. I managed to find a PDF version and skimmed through it and it is the novel I remembered.

>3 Bargle5: Yes, as sueelleker also identified, this is the novel I remember reading.