Even though kidney stones seem to be one of the oldest disorders recognized by medicine, the exact processes by which they form and grow remain unknown. Significant progress has been achieved in our understanding of the pathophysiology of ten different types of stones, including the most common type, the idiopathic calcium oxalate stone former, thanks to the new digital endoscope and extensive renal physiological studies conducted on well-phenotyped stone formers. Based on our findings and those of others studying model systems, four distinct mechanisms for kidney stone formation have been proposed. It appears that the main way stones are formed in patients with hypercalciuria is by calcium oxalate crystals growing over Randall's plaque sites. In most stone phenotypes, overgrowths of the extremities of Bellini duct plugs have been observed; do these overgrowths lead to clinical stones? The cystinuric stone formers' microlith production appears to be limited to the lumens of their dilated inner medullary collecting ducts. Finally, it is suggested that cystinuric stone formers create their stones in free solution in the presence of several small, oval, smooth-looking calyceal stones that appear yellow. This article reviews the scientific evidence for these four different types of stone production and uses it to propose new areas of study. Moreover, it provided information on the pathology of kidneys, especially the different types of stone formation, mechanisms, complications, and management.