This book explains the fundamentals of CONTROLLED 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. Now no tedious Moody chart evaluatons . Thousands of instances of Colebrook can be solved in single worksheet now with this method. No VBA/MACRO/SOLVER/USER DEFINED FUNCTIONS. A simple worksheet concept All this techniques need manual interventions. The method discussed in this book is by equations and so it is all automatic once triggered. The fixed point iteration discussed is well controlled and have freedom to input a seed value, number of iterations etc. and to check the accuracy digits. No differentiations, No need of any theorems like Newton Raphson 15 digit stabilization by iteration: Within fraction of second, we can achieve a 15 digit stabilization, which means ultimate numerical capability of computers utilized by this method. Thousands of such solving loops in single workshet: There is no limits on how many such equations can be independently solved. Your system memory decides the upper limit of thousands of equations that you can handle in a single sheet No manual intervention needed after equations and algorithms set up Simple, no-complication algorithms No 'Devide by zero' error For those who wont believe macros and VBAs - A clean worksheet concept A new version of this book is available: Solving Colebrook Equation for Pipe Design, Sizing and Optimisation Calculations: Solve Within Excel Worksheet - No VBA, MACRO, UDF of SOLVER