Business managers are advised to distinguish between arrest records and conviction records, because arrested persons may not have been tried or convicted of any crime. Another article notes that some eavesdropping is legal, while some is not and that technical surveillance countermeasures equipment and personnel vary widely and that telephone analyzers and related equipment cannot always detect telephone eavesdropping. A review of James Schaub's book "The Ultimate Security Survey" concludes that this book presents helpful survey questions and covers basic business espionage threats. Other articles focus on surveillance equipment and security issues related to the use of on-line computer network services such as the Internet.