Any suggestions on a good starting point as in books?

As you are new to Perl, the obvious answer is Learning Perl - see this review by perl514. There's also Beginning Perl which is quite old now and Modern Perl which is newer.

I need to start parsing large logs and patch assessment logs, heavily.

You might also look at Data Munging with Perl in that case.

There will also be many modules which can help, so there's no need to re-invent the wheel. eg. Apache::Log::Parser, HTTPD::Log::Filter, Parse::AccessLogEntry, AnyData::Format::Weblog, etc.