Dr. Yaqoob's research interests focus on high-energy observational and theoretical probing of the physical properties of astrophysical sources using observations. He has published papers on various topics that include: physical processes in black-hole accretion disk systems and their environment (mostly active galactic nuclei, or AGN, and quasars but including X-ray binary systems); blazars (including TeV observations); X-ray and UV absorption and photoionized outflows and inflows in AGN and quasars; high spectral-resolution X-ray spectroscopy; X-ray signatures of strong gravity effects and black-hole spin; X-ray reflection spectra from accreting sources; power spectra, spectral and temporal variability; normal and starburst galaxies; AGN unification; low-luminosity AGN; Cosmic X-ray background; coordinated multi-wavelength and multi-mission monitoring campaigns of AGN; a high~$z$ cluster of galaxies; absorption in the warm/hot intergalactic medium (WHIGM); statistics; analysis methods; numerical and Monte Carlo modeling. One of the models developed, mytorus, can be used for direct spectral-fitting analyses of X-ray data, and was made publicly available, and widely used in the literature.