Amazon.com (ISBN 006080825X, Paperback)

When advertising executive Victor Dean dies from a fall down the stairs at Pym's Publicity, Lord Peter Wimsey is asked to investigate. It seems that, before he died, Dean had begun a letter to Mr. Pym suggesting some very unethical dealings at the posh London ad agency. Wimsey goes undercover and discovers that Dean was part of the fast crowd at Pym's, a group taken to partying and doing drugs. Wimsey and his brother-in-law, Chief-Inspector Parker, rush to discover who is running London's cocaine trade and how Pym's fits into the picture--all before Wimsey's cover is blown.