AutomapServiceBehavior: This avoids multi threading issues with Automapper in a class library used by WCF. A static MapperConfig class is called by the service behaviour.

AutomapServiceBehavior.cs

namespace ServiceLayer
{
    using System;
    using System.Collections.ObjectModel;
    using System.ServiceModel;
    using System.ServiceModel.Channels;
    using System.ServiceModel.Description;
    using LAI.Data.Controllers.Mappers;

    /// <summary>
    /// Registers AutoMapper for the calls to data controller methods.
    /// </summary>
    public sealed class AutomapServiceBehavior : Attribute, IServiceBehavior
    {
        /// <summary>
        /// Provides the ability to pass custom data to binding elements to support the contract implementation.
        /// </summary>
        /// <param name="serviceDescription">The service description of the service.</param>
        /// <param name="serviceHostBase">The host of the service.</param>
        /// <param name="endpoints">The service endpoints.</param>
        /// <param name="bindingParameters">Custom objects to which binding elements have access.</param>
        public void AddBindingParameters(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase, Collection<ServiceEndpoint> endpoints, BindingParameterCollection bindingParameters)
        {
            MapperConfig.RegisterMap();
        }

        /// <summary>
        /// Provides the ability to change run-time property values or insert custom extension objects such as error handlers, message or parameter interceptors, security extensions, and other custom extension objects.
        /// </summary>
        /// <param name="serviceDescription">The service description.</param>
        /// <param name="serviceHostBase">The host that is currently being built.</param>
        public void ApplyDispatchBehavior(ServiceDescription serviceDescription, System.ServiceModel.ServiceHostBase serviceHostBase)
        {
        }

        /// <summary>
        /// Provides the ability to inspect the service host and the service description to confirm that the service can run successfully.
        /// </summary>
        /// <param name="serviceDescription">The service description.</param>
        /// <param name="serviceHostBase">The service host that is currently being constructed.</param>
        public void Validate(ServiceDescription serviceDescription, System.ServiceModel.ServiceHostBase serviceHostBase)
        {
        }
    }
}

MapperConfig.cs

namespace DataAccessLayer
{
    using AutoMapper;

    /// <summary>
    /// Represents the mapper configuration.
    /// </summary>
    public static class MapperConfig
    {
        /// <summary>
        /// Registers the map.
        /// </summary>
        public static void RegisterMap()
        {
            Mapper.Initialize(map =>
            {
                map.AddProfile<ProfileOne>();  
                map.AddProfile<ProfileTwo>();     
            });

            Mapper.AssertConfigurationIsValid();
        }
    }
}

Service.svc.cs

namespace ServiceLayer
{
    using System.ServiceModel;

    /// <summary>
    /// Represents a service.
    /// </summary>
    [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerSession), AutomapServiceBehavior]
    public partial class Service : IService
    {
        /// <summary>
        /// Do stuff.
        /// </summary>
        public void DoStuff()
        {
        }
    }
}