The Time Ships by Stephen Baxter
The Time Ships won the John W. Campbell and Philip K. Dick awards.
This book was written to be a continuation of the adventures of the time traveler from H. G. Wells' The Time Machine. Baxter has attempted to write the story in a style and with a perspective of someone from Wells' era in England.
Nevertheless, the actual adventures are not necessarily what one might have gotten from Wells had he written a sequel only a few years after the original book. When the time traveler begins his second adventure, he finds himself in a different future than he experienced in The Time Machine. Morlock-appearing "men" have built a Dyson sphere around the Sun at the orbit of Venus. The sphere is made of programmable matter that can extrude furniture as needed, make food appear, etc. It's a vast world of computers and information with the goal of accumulating all possible knowledge. They've corrected Earth's axial tilt and slowed its spin. Being outside the Dyson sphere, the Earth is dark and used for raising their children. These are the kinds of feats one finds in modern SF, not in SF of the 1890's. (Which is not to say Wells wasn't extraordinary for imagining a time machine when he did.)
Towards the beginning of the book we get an explanation for the means by which the time machine works that is in line with Wells' writing. Later in the book, characters try to make sense of it in terms of more modern physics. I'd have preferred if the book had not tried to rationalize it. If you need to include some implausible tech, just do it - don't "explain" it.
The traveler's adventures continue with him accompanied by a "Morlock". He goes back to visit his younger self when he was first working on the idea of time travel. That leads to a discussion of time travel paradoxes. Next, they are taken by a time traveling section of the British army. In this altered future, WWI has been going continuously to 1938. The 1938 they are taken to is one of air raids of missiles delivering bombs and poison gas. The main part of London is covered by a concrete and steel dome, cutting out the Sun.
He travels back 50 million years in an uncontrolled time machine. Later he finds the time traveling British troops of WWI find their way there - and the war pays them a visit as well.
An on-going theme - in the human parts of the Dyson sphere and the alternate WWI - is the insanity of war and how the logic of war perpetuates war.
After another uncontrolled flight through time, he finds himself in a far future of machine life that is not satisfied with being limited to just one universe or history line.
The book is an exploration of the ideas and possible consequences / potentials of time travel. Some readers might wish for a more extensive exploration of each of the futures / pasts that are visited in these adventures. Some readers may find some dissonance in the linking of Wells' old-school SF and the modern SF vistas. The book actually ends with a section that is more like what Wells might have written - but this, too, is only partially explored.
Perhaps, I've spent too much time on (what seemed to me to be) the weaknesses. The Time Ships is a good book. It's just my way of doing things to try to let you know what elements may be significant to some tastes.