"Brewing Microbiology" is a great book if you want to really understand well what the title of the book spells out. The book does not really go into brewing chemistry IE water profile stuff and the like. It concentrates on yeast, yeast genetics, and other microbial concerns of brewing. I bought the newest edition because of my internship as a biotech major QA intern at a brewery this semester. I found the book to be helpful at a more advanced level but my internship was not as in depth as the book allows. I also was able to get my school to buy a couple Bamforth books.
Author: Bamforth, Charles W.
Book: Beer: a quality perspective
ISBN: 9780126692013
Author: Bamforth, Charles W.
Book: Beer: tap into theart and science of brewing
ISBN: 9780195154795
Author: Bamforth, Charles W.
Book: Standards of Brewing
ISBN: 9780937381793
The three preceding texts I gleaned off of probrewer as recommended books that I forwarded to my librarian. He was able to buy "quality perspective", and "standards of brewing". I am still eagerly awaiting the "tap into the heart and science of brewing" text.
Also as ajdelange suggested the DeClerck book is also a valuable read. I was fortunate enough to borrow that off one of the brewers I was working with. You can also go to your local library and probably use the computers for journal access there to search for brewing related academic papers. I have found a couple using my school's research resources that I have saved for future use.