Two books from Eric F Russel that I like particularly are "Sinister barrier" where humans are prey to another previously unknown earthly species and "Sentinels

Two books from Eric F Russel that I like particularly are "Sinister barrier" where humans are prey to another previously unknown earthly species and "Sentinels from space" where humans experience a kind of metamorphosis when they die, enabling them to join a truly interstellar society.