Control of x-ray processes using intense optical lasers represents an emerging scientific frontier one which combines x-ray physics with strong-field laser control. The past decade has been one in which intense lasers at optical wavelengths have expanded our ability to control the behavior of isolated atoms and molecules. It is now routine to produce focused intensities of 10¹⁵ W/cm². An intensity of 10¹⁵ W/cm² corresponds to a field of ~ 10 Volts/Angstrom, comparable to the atomic field binding outer-shell electrons. By exposing an atom to an external field of this magnitude it becomes possible to modify x-ray absorption cross sections in a controlled way. This allows one to use x-rays to gain deeper insight into strong-field processes. Additionally, strong electromagnetic fields may be used to control the propagation of x-rays through a medium. Gas phase systems are particularly suitable for illustrating basic principles underlying combined x-ray and laser interactions. Three different scenarios for modifying resonant x-ray absorption near an inner shell edge will be discussed: 1) Strong-field ionization at 10¹⁴-10¹⁵ W/cm², 2) laser dressing to modify the electronic structure of atoms at 10¹²-10¹³ W/cm² and 3) control of resonant x-ray absorption by molecules by laser-induced spatial alignment at 10¹¹-10¹² W/cm².

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