A tonneau cover assembly located over a cargo bed of a truck, wherein the cargo bed is located adjacent a cab section of the truck, and wherein the cargo bed is bounded by a first wall and a second wall spaced apart from the first wall, the tonneau cover assembly comprising: a base panel that extends over the cargo bed of the truck; at least one cover section that selectively shrouds the cargo bed and is located adjacent the base panel; at least one rail; wherein the at least one rail is located adjacent a first wall of the cargo bed; and a bracket located on the rail; the tonneau cover assembly further comprising: a tie-down block assembly which includes: a block having a first surface and an arm that extends from the block and is spaced apart from the first surface; wherein the arm includes a second surface; wherein the first surface is spaced apart from the second surface; and a bolt that includes a bolthead and a shaft extending from the bolthead wherein the bolthead is wider than a diameter of the shaft; wherein the bolthead of the bolt is fitted in an opening in the base panel; wherein the shaft of the bolt is disposed in the block; wherein the first surface of the block abuts a surface of the base panel; and wherein the second surface of the arm that extends from the block abuts the bracket located on the rail; and/or a tether assembly which includes: a hook that is selectively engageable with the bracket located on the rail; a second bracket attached to the at least one cover section; and a strap that is attached to the hook and the second bracket. a base panel that extends over the cargo bed of the truck; at least one cover section that selectively shrouds the cargo bed and is located adjacent the base panel; at least one rail; wherein the at least one rail is located adjacent a first wall of the cargo bed; and a bracket located on the rail; a tie-down block assembly which includes: a block having a first surface and an arm that extends from the block and is spaced apart from the first surface; wherein the arm includes a second surface; wherein the first surface is spaced apart from the second surface; and a bolt that includes a bolthead and a shaft extending from the bolthead wherein the bolthead is wider than a diameter of the shaft; wherein the bolthead of the bolt is fitted in an opening in the base panel; wherein the shaft of the bolt is disposed in the block; wherein the first surface of the block abuts a surface of the base panel; and wherein the second surface of the arm that extends from the block abuts the bracket located on the rail; and/or a block having a first surface and an arm that extends from the block and is spaced apart from the first surface; wherein the arm includes a second surface; wherein the first surface is spaced apart from the second surface; and a bolt that includes a bolthead and a shaft extending from the bolthead wherein the bolthead is wider than a diameter of the shaft; wherein the bolthead of the bolt is fitted in an opening in the base panel; wherein the shaft of the bolt is disposed in the block; wherein the first surface of the block abuts a surface of the base panel; and wherein the second surface of the arm that extends from the block abuts the bracket located on the rail; and/or a tether assembly which includes: a hook that is selectively engageable with the bracket located on the rail; a second bracket attached to the at least one cover section; and a strap that is attached to the hook and the second bracket. a hook that is selectively engageable with the bracket located on the rail; a second bracket attached to the at least one cover section; and a strap that is attached to the hook and the second bracket.