No older than five years, hardback like Merriam Webster's Collegiate Dictionary Thesaurus - Necessary for just the right word, or adding variety to your writing. Paperback is o.k. as long as it is a college edition. When an alternative word is found, make sure you look it up in your dictionary to verify the correct usage. A thesaurus is not a dictionary. Secretarial Handbook - Information on letter writing, filing systems, function planning, record keeping, banking, etc.
Students act as their own secretaries and a secretarial handbook provides a great general reference.
Student Guides - Gives help on writing essays, algebra and study skills. Also gives advice on student life, such as how to budget, balance a checkbook and handle a roommate. Accept who you are, and find a career that harmonizes well. You'll be happier and more successful. Every career area includes some specific paths that will be lucrative and others that will not.