The Face of X (1960), by Lionel Roberts.

Virus X (1945), by Sydney Horler.

Commando X (1967), by Poke Runyon.

The Man from Planet X No. 2: Tiger by the Tail (1975), by Hunter Adams.

Could self-aware cities be the first forms of artificial intelligence?

The Power of X (1970 edition), by Arthur Sellings.

Are we seeing the rise of Alzheimer’s horror?

Planetary Agent X (1965), by Mack Reynolds.

Echo X (1960), by Ben Barzman.

Perry Rhodan No. 16: Secret Barrier X (1972), by W.W. Shols.

Utopia Minus X (1966), by Rex Gordon

The baggy ambiguities of his genius only fit the Seventies.

The X Factor (1965), by Andre Norton.

Fritz Leiber’s SF satire The Silver Eggheads first appeared in The Magazine…

The Big X (1960 edition), by Hank Searls.

His sci-fi was notable for being pastoral and nostalgic.

Venus Plus X (1960), by Theodore Sturgeon.

So what comes next after steampunk and zombies?

Charming vs. Creepy is the battle of our age.

This pedigreed, highbrow dystopian was a godfather of the Sixties.

Put Joseph Campbell back on the shelf, already!

X (1963), adapted by Eunice Sudak from the 1963 movie X.

Tomorrow Plus X (1957 edition), by Wilson Tucker.

What elevates sci-fi plots and stories? Theme. Here’s how.