What is the difference between unclassified employees and classified employees?

(3) In contrast, unclassified employees serve at the City's pleasure. (City of Long Beach Employee Handbook ["Unclassified employees serve at the pleasure of the appointing authority"].) ¹³ Serving at pleasure means one is an at-will employee who can be fired without cause. (Bogacki v. Board of Supervisors of Riverside County (1971) 5 Cal.3d 771, 783, 97 Cal.Rptr. 657, 489 P.2d 537 [it has always been the law in California that a "public employee serving at the pleasure of the appointing authority ... is by the terms of his employment subject to removal without judicially cognizable good cause"].) Unclassified employees do, however, have a right of reversion. (City of Long Beach Civil Service Rules and Regulations 91.) Under this right, an unclassified employee who is laid-off, and who was formerly a classified employee, has the right to revert to his previous classified position.