I was doing some reading today and I came upon an old series of articles over on www.databasejournal.com by a dude called Ian Gilfillan:

• MySQL backups
• Database Replication in MySQL
• Restoring lost data from the Binary Update Log
• Optimizing MySQL: Queries and Indexes
• Optimizing MySQL: Hardware and the Mysqld Variables
• MySQL’s Query Cache
• MySQL’s Over-looked and Under-worked Slow Query Log

For the ‘type’ in SQL ‘EXPLAIN’ Ian says: from best to worst the types are: system, const, eq_ref, ref, range, index, all.
It seems this Ian Gilfillan fellow has been rather prolific.