Solving Colebrook-White equation is the most important task in any piping design and optimization calculation. Engineers find it difficult to do this task in a simple way- as any other calculation using a worksheet. The reason is that these are implicit equations and friction factor appears on both side of the equation. This book explains the fundamentals of FIXED-POINT ITERATIONS and how to solve Colebrook and other implicit equations in Microsoft Excel Worksheet, in a fully controlled fashion. The method presented gives a 15 didgit accurate solution in a fraction of seconds. Thousands of Colebrook cases can be solved in single worksheet now with this method. No VBA/MACRO/SOLVER/USER DEFINED FUNCTIONS. A simple worksheet concept Now no tedious Moody chart evaluations . Worksheet takes care everything automatically Now no aproximated equations. Why to use approximate equations when 15 digit solution is just a cakewalk? A modern method to a century old problem