William Hewitt 
Microbiological Assay for Pharmaceutical Analysis [PDF ebook] 
A Rational Approach

A user-friendly guide for the evaluation of microbiological assays, this book provides a lucid explanation of the sources of error in microbiological assay and helps analysts choose efficient assay designs that will minimize those sources of error. The author discusses microbiological assay as a branch of pharmaceutical analysis and distinguishes it from biological assay in general. He draws attention to the microbiological aspects that may not be so obvious to the chemical analyst and to the analytical aspects that may not be so obvious to the microbiologist. The book expands on the guidance given in pharmacopoeias and helps readers choose the assay design most appropriate for the purpose of their assay.