May saw books set in the future and the past.

The Arc of a Scythe trilogy by Neal Shusterman, made up of Scythe, Thunderhead, and The Toll were an interesting look at a future where humanity has overcome death and instituted an organisation called Scythes whose role is to kill a fixed number of people per year in order to keep the human race from becoming totally stagnant. Obviously something goes wrong when some of the Scythes turn out to enjoy killing a little too much and rail against the restrictions placed on the methods of how they can kill and how many. This series was really novel! An idea I haven't really seen before, executed well and the endings of the first two books were (to me) completely unpredictable. Very enjoyable Young Adult stuff.

Technicolor Time Machine by Harry Harrison of Stainless Steel Rat fame sees a movie exec set out for the past in order to make a film in a location as authentic as it gets, and able to take as long as he likes, despite the pressing time commitments of his present. This seems to be out of print and I had to buy a second hand copy printed in 1984 (it was first published in 1967!). This was also a good, fun piece of pulp fiction which I found out about when reading about the first European discoverer of the American mainland in 986 CE, Bjarni Herjólfsson, hundreds of years before Cabot and Columbus.