In reply to Serpico: Leaving aside whats been written in german,french and spanish(i know that encompass's alot!)what scientific research has REALLY been written on climbing?In defence of Eric Horst,some of what he writes seems valid.It helped my training.Other broader issues he sometimes covers of psychology(visualisation,centering),goal setting,performance v training are also useful.At the very least they act act as pointers for further reading.
No literature is substitute for all or at least one of these- time,training partners,decent training facilities and of course motivation.For a keen climber knowing how to adapt to these changing facets in their climbing is the big skill.If a book can help(even as just a guide) thats good I think.Each person surely has different needs in this respect surely?