I recently finished reading the book Capital Account: A Money Manager's Report on a Turbulent Decade 1993-2002. The book is full of investment wisdom and I would recommend purcashing a copy if you can find one.
Basically the book contains experts from their newsletter the Global Investment Review. As their site says its "...published eight times a year and contains approximately six articles. Its aim is to provide clients with Marathon's latest investment thinking and (at times irreverent) commentary on events in the business and financial world. The first GIR appeared in January 1987, shortly after the establishment of Marathon."
If you can't (or don't want to purchase the book) I would recommend at least reading the PDF copies of several of their past GIRs that are available on their internet site at:
I especially enjoyed reading these:
August 2001 MacGuffins
May 2001 Two Handled Pump