The present invention is generally directed to adhesive compositions comprising selected ratios of crystalline and amorphous polymers. In some versions of the invention, polymers capable of existing in different configurations (e.g., a polymer such as polypropylene which can exist in an atactic, syndiotactic. or isotactic configuration) is used to prepare adhesives of the present invention. As an example, a selected amount of isotactic polypropylene is blended with a selected amount of atactic polypropylene to prepare an adhesive composition having one or more performance properties (e.g., bond strength) that are superior to the performance properties of a conventional hot-melt adhesive.