Thank God not everything in the universe is explained. The wonder of not knowing for sure is what is celebrated in this Reader’s Digest compendium of curious and spooky marvels. It’s given me the dubious pleasure of being perplexed by mysteries I wasn’t even aware of, like spontaneous human combustion (a human bursts into flames unaccountably and consumes itself by its own heat), or stigmata (an affliction that causes people to bleed in the manner of Christ’s wounds on certain holy days). Not to mention UFOs and ball lightning and the oddities of everyday life.