If you aren't sure how to write "asthma" or mistake "gorilla" for "guerrilla", then Chambers School Spelling should be on your desk.
Containing more than 30,000 words, it's a serviceable and often entertaining guide. There are catchy mnemonics for common puzzlers such as "accommodation", "niece" and "yacht". Rules about the formation of plurals and suffixes are set out clearly. The text is broken up by inserts on commonly confused pairs and topics such as apostrophes that can cause even the most literate to stumble. Chambers School Spelling costs pound;6.99.