'On the Beach' by Neville Shute. Not because it is boring, -it is anything but- but because it really depressed me in those cold-war days.
The other one's author escapes me. He wrote 'The Toff' or 'The Saint' series, I think. The book is called 'Black Sunday' and is in the horror genre. Both books un-put-downable, but please don't read them!