This book highlights the developments in the design of knit spacer fabrics, and their applications. Warp knit spacer fabrics have gained prominence over weft knit counterparts in terms of applications, due to the versatility of their structures. Theoretical analysis of spacer fabric under spherical ball compression is highlighted and has been shown to agree with the experimental results. The book discusses how the validated model can be used to predict the spherical compression behaviors of knitted spacer fabrics, compressed with different radii of the spherical balls.