Administrator Guide, for example -
http://download1.parallels.com/Plesk/PP10/10.3.1/Doc/en-US/pdf/plesk-10-administrator-guide.pdf
And other docs are here
http://download1.parallels.com/Plesk/PP10/10.3.1/Doc/en-US/pdf/ Just add necessary filenames:
customizing-website-topics-in-web-presence-builder-10-4.pdf
plesk-10-administrator-guide.pdf
plesk-10-api-read-me-first.pdf
plesk-10-api-rpc-guide.pdf
plesk-10-aps-limitations.pdf
plesk-10-aps-overview.pdf
plesk-10-business-manager-administrator-guide.pdf
plesk-10-business-manager-pci-compliance.pdf
plesk-10-business-manager-quick-start-guide.pdf
plesk-10-control-panel-user-guide.pdf
plesk-10-customizing-panel-appearance-branding-guide.pdf
plesk-10-deployment-guide.pdf
plesk-10-installation-upgrade-guide.pdf
plesk-10-linux-advanced-administration-guide.pdf
plesk-10-localization-guide.pdf
plesk-10-migration-guide.pdf
plesk-10-pci-compliance-guide.pdf
plesk-10-register-additional-services.pdf
plesk-10-reseller-guide.pdf
plesk-10-sitebuilder-customer-acquisition.pdf
plesk-10-sitebuilder-user-guide.pdf
plesk-10-switching-administrator-guide.pdf
plesk-10-switching-hosting-customer.pdf
plesk-10-unix-cs-gs-module-guide.pdf
plesk-10-unix-fileserver-module-guide.pdf
plesk-10-unix-firewall-module-guide.pdf
plesk-10-unix-kav-module-guide.pdf
plesk-10-unix-system-monitoring-module-guide.pdf
plesk-10-unix-vpn-module-guide.pdf
plesk-10-whats-new.pdf
plesk-10-win-advanced-administration-guide.pdf