Who can forget Radient's business deals with a dead Indian prime minister or pseudo-partnership with the Mayo Clinic? Then there was Radient's massive loan default, the reluctant disclosure that its India joint venture was a bust and the delisting from Amex. I use the Mailbag to teach investors how best to vet biotech and drug stocks, and most importantly, how to avoid losing money in the scams, frauds or stories too good to be true. Penny stocks like Radient look cheap and therefore less risky to many investors, but as Radient proved all too well in 2011, these stocks are more often money-losing black holes. Your investing dollars go in, but they never come out. As for Chucky who wrote me back in April to crow, "Looks like you got Radient wrong you Bleep. Bleep you Bleep. " Not so much, Chuck. It doesn't happen often enough but the Mailbag can sometimes discover promising, under-the-radar biotech and drug stocks. Case in point: Amarin, which was highlighted in May 2010 when the stock was trading for around $2.50 per share. My Amarin coverage continued into 2011, highlighting the company's takeout potential following the release of strong phase III data for the lipid-lowering drug AMR101. Unfortunately, even I, the biotech skeptic, can become blinded to the downside risks as I did in August when I too blithely dismissed the early warning signs of a big Amarin sell off fueled by concerns about AMR101's patent problems. If Hep C was the biggest biotech investment story of 2011, shorting new drug launches was the biotech-trading story of the year -- and a successful strategy, to boot. It seems so cruel and counter-intuitive, but in 2011, getting a new drug approved was often the worst thing that could happen to a biotech stock. The Mailbag in 2011 spent a lot of time discussing and warning investors about the perils of new drug launches, from Somaxon Pharma's ( SOMX) Silenor sleeping pill and Avanir Pharma's ( AVNR) Nuedexta to Cadence Pharma's ( CADX) injectable acetaminophen Ofirmev and Human Genome Sciences' ( HGSI) lupus drug Benlysta. This Mailbag from May was overstuffed with some of the craziest, mouth-breathing hate emails I received all year. Stuff like this almost always marks the top of a speculative biotech bubble market. The same Mailbag, by the way, demonstrated how wrong I was this year with Spectrum Pharmaceuticals ( SPPI) and its cancer drug Fusilev.