The author is a member of The Caricature Carvers of America www.cca-carvers.org and his book is a must have for anyone contemplating making caricatures.
On the left is a bench top carving arm that can be used to hold a caricature head with a small carvers screw.
Behind the carving ledge is a carving post that can be rotated to provide various support faces to lean the carving against whilst cutting away from the holding hand. All faces of the post and ledge are covered in cork sheet to maximize grip on the carving.
Other holes are parking slots for tools not in use.
On the extreme right is a leather strip charged with sharpening compound for honing the carving knives.