Frank E. Hagan 
Research Methods in Criminal Justice and Criminology [PDF ebook] 
Pearson New International Edition

For courses in Research Methods in Criminal Justice and Criminology. Teaches research fundamentals with a grounded, real-world approach. Research Methods in Criminal Justice, 9/e teaches contemporary research methods using examples of real criminological and criminal justice studies to illustrate concepts and techniques. Hagan’s best-selling approach familiarizes students with examples of research in the field as they learn fundamental research skills. The text emphasizes sources and resources of classic and contemporary research in the field and helps students and professionals better understand the extensive diversity of research available and in progress in criminal justice. The logical organization carries students through the sequence of the research process, but is flexible enough to allow instructors to customize the text to suit their courses.