The following list below is a recommended list of books for technical writers.
I have included the ISBN numbers for easy reference to find these books online.

Technical Writing 101 – Scriptorium.com – ISBN 9780970473363

Elements of Technical Writing – Bly and Blake – ISBN 0020130856

Elements of Style – Strunk & White – ISBN 020530902x

The Artful Edit – Susan Bell – ISBN 9780393057522

Synonym Finder – Rodale – ISBN 9780446370295

Roget’s Thesaurus

Designing with Style Sheets Tables & Forms – LeMay – ISBN 1575951495

HTML Web Publishing – Stauffer – ISBN 0789814078

Any Dummy Series

One Minute Sales Person – Johnson – ISBN 0002181800

Winning without Intimidation – Burg – ISBN 1890344117

Positive Personality Profiles – Rohm – ISBN 0964108003

Your Personality Tree – Littauer – ISBN 084993169x

Writing Down the Bones – Goldberg – ISBN 9781611803082