This book is primary intended for solving problems in signals and systems with use of the MATLABr and thereby understanding the solutions clearly. This MATLAB based book has resulted from my teaching experience of undergradu- ate and graduate-level courses of signals and systems, digital image processing over the past decade. Today most students prefer watching a screen to taking notes even in class of signals and systems really needed great e®ort, so it is liable to neglect their studies. Fortunately most students are familiar with the computers and the internet and also have some expe- rience of the MATLAB software. The MATLAB is easily accessible to even a beginner, e®ective in visualization of signals, has an abundance of mathematical and engineering functions and a great °exibility for user to make new commands and functions for his or her own purpose. For the course achievement, it requires as much direct and actual experience as pos- sible since touching signals and systems for oneself is worth much more than listening, seeing, or writing down. For this purpose, we ?rst a set of 108 topics which are fundamentals in signals and systems, second introduce and discuss about each ed topic, and at last, set problems and solve the problems with MATLAB. This book consists of three chapters. The ?rst chapter introduces the basic mathematics and 3D visualization techniques with 20 topics such as sinusoid, complex exponential, sinc function, Dirichlet function, convolution integral, partial fraction expansion, orthog- onality, 3D mesh plot of 1 s in the complex plane, etc. The second chapter covers the continuous-time signals and systems with 43 topics such as Fourier series and transforms, Gibbs phenomenon, generalized impulse trains, sam- pling and dual sampling theorems, transfer function and frequency response of a linear time-invariant (LTI) system, Butterworth lowpass ?lter, 3D mesh plots of the Laplace transform of the step function and transfer functions of the LTI systems, representation of Dirac-delta impulse on the rectangular and polar coordinate systems, etc. The third chapter deals with the discrete-time signals and systems with 45 topics such as the discrete-time Fourier transform (DTFT), relationship between Dirichlet function and sinc function, relationship between the DTFT of sgn[n] and the Fourier transform of sgn(t), the di®erence of u(n) and u[n], periodic convolution, up and down samplings, the discrete Fourier transform (DFT), the z transform, pole-zero distribution, reconstruc- tion of the z transform from the samples on jzj = r, analog to digital ?lter conversion, correction of impulse invariance transformation, digital Butterworth ?lter, 2D and 3D visualizations of 1D ?ltering, single tone estimation, deconvolution, etc. In appendix A, some basic and useful formulas derived and used in the book are sum- marized. Appendix B shows the evaluation of the area under sincN(t) for N = 1 2 by a partial area sum technique. In appendix C, the new 14 MATLAB functions developed for this book are included.