Simple thermal management of large laser diode arrays can be accomplished by directly mounting laser diode material in a grooved substrate, This "Monolithic" assembly method dramatically simplifies the thermal path from the laser junction to the final user specified heatsink. For pulse width <lms, high density bar packing of 30 to 40 bars per cm is possible , pulse widths from 5 to 10 ms can be supported with packaging densities of 10 to 20 bars per cm and for those who need pure CW, typically 4 to 8 bars per cm arrays can be fabricated all while utilizing simple coolers. For those requiring the highest level of performance the "Bars in Grooves" packaging technology can be hybrid with, impingement, macro I micro channel or even pin type coolers. While Beryllium Oxide (BeO), Aluminum Nitride (AlN) and copper are typical base materials presently utilized for mount fabrication, it is only a matter of time before other very high thermally conductive material, such as diamond become commercially viable options ... The fabrication technology has the added benefits of precision location of emitters: for use with collimation lens. array repairability, bars can be removed and replaced. and requires minimum assembly fixturing, bars self align. and the technology scales both for array size and volume requirements.. The most important factor is that the "Bars in Grooves" assembly method produces laser diode arrays of the highest quality combined with the lowest cost!!