Humanity is in grave and present danger of extinction. Americans' are in grave and present danger of losing their precious freedoms. There are man-made threats that may or may not be reversible. There are natural universal threats that are irreversible. This book explores a wide range of existential threats. Some of these are almost daily in the collective consciousness. Some are well known but more or less ignored. Some threats are virtually unknown to all except the scientists whose warnings are often unheeded.