Sean Randall reviewed Sixth Column by Robert A. Heinlein
Review of 'Sixth Column' on 'Goodreads'
5 stars
This is one of my favourite Heinleins. The stereotyping of the invaders is a little dated and I can't quite help but feel there's a seam of satire running beneath what is, to all outward appearances, an action story. Still, if you're new to him and want a taste of his paramilitary and scientific exposition without too much fluff and are looking for a cracking yarn to boot, this may be worthstarting with.