The given series is an arithmetic series with a common difference of 2 and a first term of -39.
The last term can be found by solving $-1 = -39 + (n-1)(2)$, where n is the number of terms in the series.
Simplifying, we get $n = 20$.
The sum of an arithmetic series can be found using the formula $S = \frac{n}{2}(a_1 + a_n)$,
where S is the sum, n is the number of terms, $a_1$ is the first term, and $a_n$ is the last term.
Plugging in the values, we have $S = \frac{20}{2}(-39 + (-1)) = \frac{20}{2}(-40) = -400$.
Therefore, the sum of the given series is $\boxed{-400}$.
The answer is: -400
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
Find the sum: $(-39) + (-37) + \cdots + (-1)$.

### Answer:
