Try
SELECT *
FROM myTable Emp1
WHERE (N-1) = (
SELECT COUNT(DISTINCT(Emp2.Salary))
FROM Employee Emp2
WHERE Emp2.Salary > Emp1.Salary)
Here N is the nth maximum you want e.g. 2nd or 3rd maximum salary.
If you are using SQL Server 2012, the answer is slightly easier.
SELECT * FROM myTable
ORDER BY Salary DESC
OFFSET N ROWS